Pollen Grains of Nigerian Plants

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1 Grana ISSN: (Print) (Online) Journal homepage: Pollen Grains of Nigerian Plants M. A. Sowunmi To cite this article: M. A. Sowunmi (1973) Pollen Grains of Nigerian Plants, Grana, 13:3, , DOI: / To link to this article: Published online: 01 Sep Submit your article to this journal Article views: 368 View related articles Citing articles: 36 View citing articles Full Terms & Conditions of access and use can be found at Download by: [ ] Date: 21 November 2017, At: 23:10

2 Grana 13: , 1973 POLLEN GRAINS OF NIGERIAN PLANTS I. Woody Species M. A. Sowunmi (Received July 15, 1973) Downloaded by [ ] at 23:10 21 November 2017 ABSTRACT So\vunmi, hl. A. (Dept. of Archaeology, University of lbadan, Nigeria). PoNeri grains of Nigerian plants. I IVoody species. Grana 13: , PolIen grains from 150 Nigerian \voody plants, comprising over 60% of the recognised climatic indicator species of the forest and savanna zones, are described, many of them for the first time. 73 are also illustrated. Some of the observations made are compared \tith those of earlier investigators. Intra-specific variations \\ere noted. INTRODUCTION This paper is the first in a series on the pollen flora of Nigeria. The pollen grains described are those of climatic indicator species of forests, i.e. primary and secondary rain forests, and swamp forests, and savanna, i.e. derived forest in the Guinea and Sahel zones, these being the major vegetation zones in Nigeria. The plants chosen comprise approximately 62% of the 240 major climatic indicator species. Subsequent papers in the series will deal with the remaining indicator species, other woody plants, herbs, and food crop plants. At present, only short descriptions of pollen grains from some Nigerian plants exist, which are scattered over several journals. This is the first attempt to present a largzr assemblage in a composite and detailed manner. Altogether pollen grains from 150 woody plants in 47 families have been described. About 50 of them had been previously described or just.mentioned very briefly. These earlicr observations are compared with the present situation, where appropriate. For a full list of references on earlier studies see Thanikaimoni s Index bibliographique (1972). The need for a publication on the pollen morphology of Nigerian --._...,. plants is at least two-fold: Firstly, to provide additional characters for use in plant taxonomy, and secondly, to serve as a reference material for pollen analysis of Quaternary deposits. Realising that a complete coverage of all woody plants, and the whole flora of Nigeria, will take several years of team work to accomplish, the decision was made to publish the information accumulated by the author over the last five years as a beginning, in the hope that this will aid in the interpretation of Quaternary pollen diagrams. MATERIALS AND METHODS The polliniferous materials examined were obtained from both herbarium and fresh specimens. The former were obtained from the Federal Department of Forest Research, Ibadan, Nigeria (FHI), or as otherwise indicated, and the latter from various parts of Nigeria. The materials were acetolysed (Erdtman, 1969). Separate preparations of grains treated with 5% KOH, with or without alcoholic safranin. staining, were also made. The treated grains were mounted in glycerine jelly and the slides sealed with paraffin wax. The figures recorded for the various pollen grain dimensions were generally the average of measurements of 10 grains (mean and standard deviation). When fewer grains were measured ca precedes the figures. The dimensions of sexinous processes were recorded separately. The density of these processes was estimated by counting within an area of 15 pm*. The terminology is after Erdtman (1952, 1966, 1969), and Faegri & Iversen (1964). Grana 13

3 146 hi? A. Soivirririii DESCRIPTIONS OF POLLEN GRAINS' (Polar axis = P; Equatorial diameters = E, El, E?.) Agaraceae Drncaeria nrboren Link Herbarium material. Sierra Leone Morton and Gledhill3022, FHI. Pollen grains heteropolar, bilateral; 1-colpate; elliptical in polar view (I?, El 72.3 k2.7 jtm, E, 46.0 & 3.7 pm. Sexine smooth, pertectate, densely infrabaculate (distinct LO-pattern). NPC: 133. Colpus comparatively long (66.8 t3.4 pn), either of the same width throughout or sharply constricted at the distal pole, ends rounded and with distinct margins. Exine 1.9 prn thick. Tectum 0.5~0.1 pm thick, baculate zone 0.9 t0.3 /cm thick, and foot layer 0.5 ko.1 /im thick. Arincnrdiaceae Laririea riiicrocarpa Engl. & K. Krause (PI. 1, Figs. 1-2). Herbarium material. Ilorin Onyeachusim and Binuyo, FHI. colporate; peritreme-prolate (P 29.4 pm, E 19.4 pm). Sexine subtectate, finely striate. NPC: 355. Colpi 26.3 pm long, 2.4 y-n wide, constricted medially and tapering towards the ends, with conspicuous margins.(l.l pm wide) which are absent in the region of the ora; about 13% of the grains examined were syncolpate.' Apocolpium diameter 2.9 pm. Ora indistinctly demarcated. Exine about 1.1 pn wide, stratification indistinct. Lirae 0.4 pm wide, simpli-duplibaculate. Striae 0.4 Iim wide. Marigifera irirlica Linn. Fresh material. Ibadan Sowunmi 20. colporate; goniotreme, sides convex-subprolate (P 30.0 k 1.4 pm, E 26.0f 1.4 pm). Sexine subtectate, striate to reticulate. NPC: 345. Colpi 24.0 & 1.5 /cm long, 1.7 k0.2 pm wide, either of the same width throughout or slightly constricted medially. Apocolpium diameter 6.5 pm. Ora markedlyelongatedtransversely,(7.5 & 1.0 % 10.3 & 1.Opm). Exine 2.2 jtm wide at the mesocolpia, thinner at the apocolpia, tapering towards apertures. Sexine distinctly striato-reticulate. Lirae and/or muri 0.4 ko.1 ttrn wide, simplibaculate. Striae and/or lumina For list of terms used see p ko.1 pm wide. Tectal part of sexine 0.7 ko.1 pm thick, bacules prn high, foot layer, 1.0_+0.1 pm wide. Sclcrocnrja birreo (A. Rich.) Hochst. Herbarium material. Achioli, Uganda H. C. Darkins, FHI. colporate; lobate-subprolate to prolate, the latter in about 27% of all grains examined (P 30.0 iim, 34 pm, E 25.5 pm, 24 pm). Sexine subtectate, striate to striato-reticulate. NPC: 345. Colpi about 26.9 pm long, about 2.0 pm wide, may be slightly constricted medially or may taper towards the ends, with distinct margins. Apocolpium diameter about 2.5 pm. Ora usually indistinctly delimited, but may appear longitudinally elongated, length about 3.4 pm, width same as colpi. Exine thickness and stratification difficult to ascertain, (about 1.1 pm thick). Striate pattern fine but distinct, striatoreticulate in parts. Lirae 0.4 pm wide, simplibaculate. Striae 0.4 pm wide. A previous description of the pollen grains of this species by Lobreau et al. (1969) does not differ significantly from the above. Aririor iaceae Aririorin seriegnlerisis Pers. (PI. 1, Fig.3). Herbarium material. Niger Peyre de Fabregues 1650, Montpellier. Pollen grains united in rhomboidal or tetragonal tetrads, individual grains heteropolar, bilateral, with one proximal leptoma; shape of individual grains variable, appears to be rounded-triangular (tetrad diameters 89.6 /tm x 97.2 pm, individual grains about 45 pm). Sexine subtectate, ornate. NPC: 111. Leptoma of varying shape and size, but generally large and occupying a significant part of the proximal face. Exine 2.7 Itm thick, coarsely ornate, in the central areas solitary bacula are sometimes found; in optical section some bacula appear to be branched. Tectal part 0.6 prn thick, bacula 1.4 pm high, foot layer 0.7 pm thick. The genus Aririorin was described by Walker (1971) as possessing only tetragonal tetrads. Aririoriirliiiriz iiiaririii(0liv.) Engl. & Diels (PI. 1, Fig. 4). Herbarium material. Ondo Lowe 661, Botany Department, University of Ibadan, Ibadan. Pollen grains united in tetrads, type of tetrad variable, mostly tetragonal, but may be rhomboidal or, apparently, decussate; the pollen grains of the

4 148 hi. A. Sowiintiri tetrads easily become separated after acetolysis; individual grains heteropolar, bilateral, with one proximal leptoma; shape of individual grains variable, symnietrically elliptical, rounded triangular, or nearly circular (tetrad diameters 197.8pm x 243.7pm, individual grains pm x pm-only elliptical grains measured). Sexine subtectate, scrobiculate. NPC: 111. Leptoma of very variable shape and size, margin ragged, elongated or triangular, generally very large as in Annonn senegalensis. Exine thickness difficult to ascertain. On the distal face, pattern is coarsely scrobiculate, luniina 3.3 pm wide, mostly circular but sometimes elongated. Some minute bacula occur in the luniina; muri 3.5 Itm wide, supported by a single row of stout bacula and two or more rows of very minute ones. On the proximal face the exine immediately around the aperture has narrow, elongated lumina, grading into a +vermiculate pattern, but with circular lumina in the remaining parts; the muri are supported by only small bacula in one or more rows, stout bacula, as sex on the distal face arc absent. Bacula of the stout type have capita diameter 4.0 pm, and are sometimes fused laterally in pairs. The pollen grains are similar to those of Arrriorra setiegalelrsis. This species was described by Walker (1972) as possessing only tetragonal tetrads. The dissimilarity between the exine pattern on the distal and proximal faces was not emphasised. Aioriodora tetiriifolia Benth. Fresh material. Ibadan 1968, Sowunmi et al. 29. Pollen grains united in tetragonal or rhomboidal tetrads; individual grains atreme or seemingly 1- colpoidate; elliptical to more or less triangular (tetrad diameter k 12.6 pm, individual grains (75.8 k 3.2 x 56.6 i5.9) pm). Sexine subtectate, perforate. Most of the grains apparently lack apertures, though some appear to have a colpus-like furrow which often has irregular and very thin margins. Exine 1.6 prn thick, undulating. There appears to be an outer, more loosely attached wall roundeach grain. This outer wall was not seen in mature grains treated with 5% KoH, but was present in immature grains similarly treated, as well.as in both immature and mature acetolysed grains. Tecturn 0.8 k0.2 pm thick, irregularly perforated, supported by bacula, some of whose upper parts project beyond the sur- face of the grain. Baculate zone 0.5 k0.2 pm thick, and foot layer 0.3 ko.1 prn thick. N.B. All measurements were made on KOHtrcated grains because grains became distorted by acetolysis. Although Walker (1971) described the tetrads as being tetragonal and Canright (1963) referred to them as rhomboidal, the prescnt investigation shows that both tetrad types occur, the former being predominant. Most of the grains lack apertures, as reported by Canright (ibid.), but some havc a colpus-like opening, in agreement with Walker s (ibid) observation, though the opening is not as clearly defined as that recorded by Walker (ibid, pl. 31: 1). Apocyimrene Alstotriu booetri De Willd. Herbarium material. Ibadan Onochie, FHI. colporate; goniotreme, sides convex-suboblate (P 24.0 & 1.6 pm, E 29.0 k2.1 pm). Sexine pertectate. NPC: 345. Colpi often not clearly demarcated, ora (3.1 ko.1 x 3.6 x 0.5) pm, nearly circular or transversely elongated, each bordered by an annulus 1.OkO.2 pm wide. Exine 1,450.1 pm thick in the inter-apertural regions, considerably thicker at the apertures (4.7 _+ 0.5 pm thick), strztification indistinct. Sexine punctate (OL-pattern). Fiitrtutnia dusticu (Preuss) Stapf. (PI. 1, Figs. 5-6). Fresh material. Ibadan Sowunmi et al. 8. porate; goniotreme to peritreme, sides convexsuboblate (P pm, E 41.2 ko.8 pm). Sexine subtectate, ornate NPC: 344. Pores 5.1 k0.8 pm in diameter, each with a distinct, granulate annulus (3.1 k0.5 /cm wide) of irregular outline. Apoporiurn diameter pm. Exine pn thick, not homogenous throughout, ornate for the most part. Tectal part of sexine in some areas appears to be very thin and faint, with both small and stout bacula distinctly visible beneath (LO-pattern), in other areas it is apparently smooth and thin with either short and narrow, or small and round perforations. Holurrlrerro floribritidu (G. Don) Dur. & Sehinz. Fresh material. Ibadan Sowunmi et al. 41.

5 Pollerr of Nigerian plants. I 149 Downloaded by [ ] at 23:10 21 November 2017 porate, very rarely 4 or 5-porate; peritreme to goniotreme, sides convex-suboblate (P 26.7 pm, E 30.7 Icrn). Sexine subtectate, perforate, NPC: 344 (444, 544). Pores 4.6 pm ~3.9 pm, each with a distinct coarsely granulate annulus, 2.7 pm wide. Apoporium diameter 0.8 pm. Exinc 1.2 Itm thick in the inter-apertural regions, thicker at the apertures, (2.1 Itm), with a distinct LO-pattern, but +vermiculate in parts. Tectum 0.3 /tm thick, baculate zone 0.5 pm and foot layer0.4pm; at the apertures the three layers are 0.8 pm, 0.9 Itm,. and 0.4 pm, thick, respectively. The pollen of this species are somewhat similar to those of Frrritrrriiia elastica, though smaller. Raircolfin coriiitoria Afzel. (PI. 1, Figs. 7-9). Fresh material Ibadsn Sowunmi et al. 39. colporate, (occasionally 4-colporate, viz. in 4.6% of the 240 grains examined), syncolpate; goniotreme, sides convex to straight-suboblate (P ca pm, E 60.5 f4.6 pm). Sexine subtectate, reticulate. NPC: 345 (415). Colpi united at the poles (syncolpate condition not seen in all grains), ca. 6.0 pm wide, tapering towards the poles, margins $istinct, covered with thin granulate membranes which become very coarse at and around the poles. On either side of each colpus is a markedly looped or ring-like cavity, covered with a thin membrane; this membrane was often found to peel away to a varying extent; in some grains the loops of adjacent colpi are united, forming a spiral ova the grains. Ora large, longitudinally elongated, ca. 8.8 /ern long, 2.0 prn wide, each with a wry narrow annulus. Exine thin in inter-apertural regions (1.4 ko.l,urn thiclc), thizker at apertures, 2.4 k0.4 /tm thick. Stratificitio.7 indistinct. The conspicuous reticulate pattern at the poles is in sharp contrast to the very fine pattern over the remaining parts of the grains. The grains of this species are quite unusual because of the cavities surrounding the apertures. No previous descriptions have been published so far as the author is aware. A raliaceae C~rssomin bnrferi Seemann Herbarium material. Abeokuta Dararnola, FHI. Pollcn grains isopolar, radially symmetrical; 3- colporate; goniotreme, sides usually concave, but may also be convex or straight-prolate (P pm, E 26.4 k0.9 pm). Sexine subtectate, reticulate. NPC: 345. Colpi prn long, pm wide, conspicuously constricted mcdially, margins distinct (2.3 f0.2 pm wide) but absent at thc constriction. Apocolpiurn diameter prn. Om transversely elongated, 2.5 ko.1 I m long, /tm wide, not always distinctly demarcated. Exine 1.7 Irrn thick. S-xine reticulate. Muri 0.5 ko.1 pm wide, supported by a row of bacula, curved in some places and discontinuous over small areas. Lumina 1.1 k0.3 pn wide. Tectal part of muri 0.4 k0.1 pm thick, infratectal baculate zone 0.8 f0.3 pm thick, and foot layer 0.5 ko.1 pm thick. Acicerirriaceae Aciceiirria ofricono P. Beauv. Herbarium material. Ikorodu Okafor and hlacaulay, FHI. Pollen grains isopolar, radially symmetricsl; 3- colporate; peritreme-subprolate (P 31.2 f0.4 pm, E 25.2 k2.0 pm). Sexine subtectate, reticulate. NPC: 345. Colpi provided with granulate membranes which often protrude very conspicuously beyond the surface of the grain, especially after acetolysis. Apocolpium diameter 6.8 pm. Ora more or less circular, faintly delimited. (The apertures in this species could not be measured as they were not well displayed.) Exine 1.6 /rm thick, tapering towards tte apertures. Sexine reticulate. Muri 0.5 pm wide, supported generally by one, but sometimcs by two rows of bacula. Lumina 1.0 /tm wide. Tectal part of muri 0.5 k0.1 pm, infratectal baculate zone 0.6 i0.2 pm thick, somc bicula appzar to be branched apically, and foot layer 0.5 ko.1 /tm thick. Erdtman (1952, 1966) referred to the pollen as being (2-)-3 colporoidate, scxine reticulate. No 2- colporoidate grains have been observed by the present author. Such grains probably occur only rarely and might have been missed. The conspicuously protruding colpal mmbranes W2re not mentioned in Erdtman s (ibid.) short description. Bnlairitaceae Balairites negypfiaca (Linn.) Del. (PI. I, Figs ). Herbarium material. Bornu Onochie, FHI. colpxate; pleurotreme, sides convex, angles rounded-prolate spheroidal (P 33.2 pni, E 29.1 pm), subtectatc. NPC: 345. Grnrra I 1

6 150 hf: A; Sowiirirni Colpi 26.0 /tm long, 1.8 /tm wide for most of their length, tapering towards the ends and apparently constricted mcdially. A few grains (7% of those examined) are syncolporate. Apocolpium diameter 6.1 pm. Ora distinctly elongated longitudinally (8.1 pm long, 6.3 pm wide), lateral sides often not distinctly demarcated. Exine 2.0 pm thick, with an irregular OL pattern, minutely reticulate-like; pouts slightly at apertures. Tectum 0.4 pm thick, baculate zone, consisting of prominent and densely spaced bacula, 0.6 pm thick, foot layer 0.2 pm thick, nexine, 0.3 /rm thick, nexinet 0.5 pm thick and 1.6 pni thick at the apertures. Brief.descriptions by Erdtman (1952,.1966), Horowitz & Baum (1967) and Maley (1970) agree with that of the present study. Bigrroiiiacene Newboiildia lnecis (P. Beauv.) Seeman ex Bureau. Fresh material.' Ibadan Sowunmi 16. colpate; pxitreme-subprolate (P 53.3 k3.3 /mi, E 42.5 k3.2 pm). Sexine subtectate, reticulate. NPC: 343. Colpi long (45 k3.0 pni long, pm wide), tapering towards the ends. Apocolpium diameter 11.4k1.2 pm. Exine 2.1,mn thick, somewhat thinner towards colpi. Sexine reticulate. Muri 0.6 ko.1 /rm wide, supported by a distinct row of bacula. Lumina 1.9kO.5 pm wide, bacula which are smaller than the infratectal ones occur within some lumina. Tectal part of muri 0.8 fo.l pm thick, infratcctal baculatc zone 0.7 f0.2 Icm thick, and foot layer 0.6 ko.1 pm thick. Spathoden cnriiporiiilata P. Beauv. Fresh material. Ibadan Sowunmi 5. colpate to 3-colporate; peritreme-subprolate (P 48.7 f2.4 /mi, E 37.1 k2.1 pm). Sexine subtectate, reticulate. NPC: 343, 345. Colpi (39.6f1.9 /tm long, pm wide). Apocolpium diameter pm. Scanning electron microscope studies revealed the presence of ora in some grains; ora small, transversely elongated. Exine 2.2 pm thick, somewhat thinner towards colpi. Sexine reticulate. Muri (0.6 ko.1 pm wide), sometimes discontinuous over small areas, supported by a distinct row of bacula. Lumina 1.7kO.4 pm Grmn 13 wide. Tectal part of muri Itm thick, infratectal baculate zone 1.1 f0.2 Itm thick, and foot layer O.S.fO.1 pm.thick. The pollen grains of Newbouldia laecis and Sparhoden cnriiporiirlafa are very similar to on: another. Boriibacaceae Boriibnx brecicitspe Sprague (PI. 1, Figs ; PI. 2, Fig. 1). Herbarium material. Benin Onochie, FHI. porate, occasionally 4-porate (8.3% of the 60 grains examined), rarely 5-porate (3.3 %) peritreme-spheroidal (E 63.5 f2.8 pm). Sexine apparently pertectate, densely infrabaculate. NPC: 344, (444, 544). Pores (5.8 f0.6 x 4.7 k0.6) pm, each with a distinct annulus (ca pm wide). Apoporium diameter [tm. Exine 2.1 pm thick, much thicker at the pores (4.0 ko.5 pn). Tectum comparatively thin (thickness 0.4 fo.l pm), provided with spinules. Supratectal spinules 1.7 f0.3 /mi high, basal diameter 0.8 to.l pm, frequency 11 per 15 /tmz. Infratectal baculate zone 0.8 fo.l pm thick, and foot layer 0.9 f0.3 pm thick, conspicuously thickened at the pores, ( pm). B. biioriopozerise P. Beuav. (PI. 2, Figs. 2-3). Fresh material. lbadan Sowunmi 1. colp(or)ate; pleurotreme, sides straight to convexoblate spheroidal (P 40.5 f2.8 pm, E 45.8 f 1.6 pm). Sexine subtectate, reticulate. NPC: 343, (345). Colpi short, (length 12.9k2.4 pm, medial width 2.4 f0.6 pm, tapering sharply towards the ends), margins distinct ( pm wide medially tapering gradually towards the ends). Apocolpium diameter 22.0 k2.4 pm. Ora longitudinally elongated, often not clesrly delimited. Exine 3.1 pm thick. Sexine coarsely reticulate, brochi large in the central part of the grains and become progressively smaller towards the angles. Muri 1.3 f0.2 pm wide, distinctly simplibaculate. Lurnina 4.5 f0.2 /tm wide, provide with bacula (2-14). Infratectal bacula generally stout and densely spaced, height 2.5 k0.2, pm, apical diameter pm, basal diameter 0.9 f0.2 jtm. Foot layer 0.6 k0.l I'm thick, considcrably thickened at apertures (4.0 k 0.6 pm). Apart from slight dimensional differences, as well as the fact that scanning electron micrographs reveal

7 Plate 2. Fig. I. Bombax brericrrspe (contd.) (x 1 250) optical streak at 4 o'clock. 9. Bcrlinia granrlifora (x 625) cross-section B. bironopozetise ( x 500). 4. B. roslnlrrnt Brachjsregia euryconra ( x 625) Danicllia olireri (x 1 250) note colpus and 0s Ceiba penrandra (x 500). (x 1 000). 22. Sgncolporate, mature grain; 13. Non-syncol Afzelia africatra (x I 000). 7. Note colpus and 0s; porate, immature grain. 14. Drfnrirrnr nrirrocnrprtnr (x 1 250) 8. Note 2 colpi at 6 and 1 o'clock positions, and a colpoid 4-colporate grain. Grorin 13

8 152 hf. A. Soiviirirni a greater number of bacula in the lumina than previously reported, Tsukada's (1964) observations are very similar to those of the present investigation. Maley (1970) recorded the presence of 2-colporate grains, but none were observed by the present author. B. costatiin1 Pellegr. & Vuillet (PI. 2, Fig. 4). Herbarium material. Ilorin Latilo FHI. colp(or)ate; pleurotreme, sides straight to convexoblate (P 38.7f1.7 /em, E 45.7k2.3 /em). Sexine subtectate, reticulate. NPC: 343 (345). Colpi short (length 10.2 f 1.2 pm, width ca. 2.8 f 0.7 /em medially tapering off to the ends). Apocolpium diameter 23.6 k0.8 /em. Ora slightly elongated transversely, often not clearly defined. Exine 3.2 pn thick, (ca. 3.9!em thick at the apertures). Sexine coarsely reticulate. Muri 1.2 p n wide, distinctly simplibaculate, rarely duplibaculate in parts. Lumina 3.7 /em wide, provided with bacula (2-8). Infratcctal bacula generally stout, height 2.7k0.4 pm; apical diameter 1.2f0.4 pn, basal diameter 0.7 k0.2 pm. Foot layer 0.5 ko.l /cm thick. The pollen grains of Boiiibnx birorlopozense and B. costclriirr1 are similar to one another (3-colporate, coarsely reticulate) and distinctly different from those of B. breciciispe (3-porate, spinulose). This observation is in close agreement with the gross morphology. For example, both B. bironopozerise and B. costatririi possess pink or orange flowers, while B. brecicirspe has white flowers. Furthermore, the numerous stamens in the latter are not grouped into five bundles as they are in the other two species (Hutchinson & Dalziel, ). B. brecicrispe and B. bironopozerise, however, are forest trees, while 8. cosratmj is a savanna tree. Ceiba peritaridra (Linn.) Gaertn. (PI. 2, Figs. 5-6). Herbarium material. lbadan Olorunfemi, FHI. colporate; pleurotreme to peritreme, sides convex to straight-suboblate (P 51.1 f 1.8,tun, E 64.2 f 1.5 pm). Sexine subtectate, reticulate. NPC: 345. Colpi 23.5 f2.9 pm long, 3.5 k0.6 prn wide medially, tapering off to the ends, margins 5.2 k0.9 /em wide. Apocolpium diameter 39.6 fo.l pm. Ora elongated longitudinally, faintly delimited. Exine 2.6 pm thick (5.2 [em thick at the colpi). Sexine coarsely reticulate, markedly heterobrochate. Muri 1.9. k0.3 /em wide, supported by one to three rows of bacula. Lumina 6.1 fl.1 pm wide, provided Drorin 13 with numerous, very small bacula (1 1-28). Tectal part of muri 1.0 k0.2 pm thick, infratectal baculate zone 0.8 f0.3 [em thick, and foot layer 0.8 ko.1 /em thick. Maley (1970) examined the apertural status of the pollen only, and supplied a few photomicrographs. Biirseraceae Coriiririphora ofricnna (A. Rich.) Engl. Herbarium material. Tchad Leonard 4232, Brussels. 4- colporate (43% of the grains examined were 4- colporate); 3-colporate grains peritreme-oblate spheroidal (P 24.4 pm, E 25.9 /ern); 4-colporate grains tetragonal, sides convex-oblate spheroidal (P 26.4 /em,'e 27.7 pm). Sexine subtectate, reticulate. NPC: 345, 445. Colpi ca /em long and ca. 1.0 /em wide in 3- colporate grains, ca. 9.8 /em long and ca. 1.5 [em wide in 4-colporate ones; usually only faintly demarcated. Ora elongated transversely in both, ca. 1.9 pm long and ca. 3.0 pm wide in 3-colporate grains, ca. 2.3 pni long and ca. 3.6 pm wide in 4-colporate ones. Exine similar in both types of grains, 1.9 [em thick. Sexine coarsely reticulate. Muri 1.0 pm wide, supported by one or sometimes two rows of bacula, slightly curved in places. Lumina 2.1 pm wide. Tectal part of muri 0.5 /em thick, infractectal baculate zone 0.6 pm thick, foot layer 0.5 pm thick, thickened at apertures (1.8 pm thick), and endexine, 0.3 pm thick. C. pedirriciilata Kotschy & Par. Herbarium material. Bornu Onochie, FHI. (4)- colporate; goniotreme, sides convex, to peritremeoblate spheroidal (P 27.4 /em, E 29.6 /ern). Sexine subtectate, reticulate. NPC: 345 (445). Colpi 10.0pm long, 1.5 /em wide medially, tapering off to the ends, faintly delimited. Ora mostly more or less rounded, 2.9 /cm x 3.0 pm. Exine 1.9 /em thick, (3.6 pm thick at the apertures), gently undulating. Sexine coarsely reticulate. Muri 0.7 pm wide, distinctly simplibaculate. Lumina 2.2 /em wide, thin sexinous strands, with bacula, occur in some lumina. Tectal part of muri 0.7 /em thick, infratectal baculate zone 0.6 /ern thick and foot layer 0.6 /em thick. Maley (1970) mentioned only the apertural status of C. clfricarin and C. pediirrcirlnto pollen, and provided a few photomicrographs.

9 Cuesalpiiiaceue Afzeh ufricatia Sm. (P1.2, Figs. 7-8). Herbarium material lbadan 1962; Ubom, FHI. pollen grains isopolar, radially symmetrical; 3- colp(or)ate; goniotreme, sides markedly concaveprolate spheroidal (P 56.9 f2.6 pm, E 51.7 k2.6 pm). Sexine subtectate, reticulate. NPC: 343, 345. colpi 24.1 k3.4 /tm long, 4.2 f0.5 pm wide, with finely reticulately-patterned membranes; the colpi appear to be united at the poles in some grains at least; alternating with each of the three colpi is a colpoid streak. Ora elongated longitudinally, hardly visible in acetolysed grains but clearly delimited in KOH-treated ones. Exine 7.9 [tm thick. Sexine very coarsely reticulate. Muri 1.6 t0.3 pn wide, conspicuously curved, distinctly simplibaculate. Bacula mostly stout, height 5.3 k0.7 pm, basal diameter 1.2 t0.2 pm, apically slightly swollen and 1.8 f0.3 pm wide; some very slender bacula occur in places. Lumina 6.8 f 1.4,mn wide, of varying shape: round, polygonal, or narrow and elongated, even in a single grain; bacula also occur within some of the lumina. Tectal part of muri 1.8 k0.4 pm thick, infratectal baculate zone 5.3 k0.7 pm thick, and foot layer 0.8 ko.1 pqthick. Erdtman (1952, 1966), described the pollen of this species as occurring in tetrahedral tetrads, but the present investigation showed that the grains occur singly. It is difficult at the mo,ment to resolve this disparity. However his description of the pollen of A. qrraiizerrsis is very similar to my description of A. ufricarin pollen. Airfhoriothn niacroplrylh P. Beauv. Herbarium material. Benin Daramola & Emiriogbon, FHI. Pollen grains isopolar to sub-isopolar, radially symmetrical; 3-colporate; pcritreme-prolate (P pm, E 30.6 pm). Sexine subtectate, striate. NPC: 345. Colpi 41.9 pm long, 3.2 prn wide, membranes project slightly beyond the exine surface in polar view, colpi margins 1.7 pm wide at and*near the poles tapering off very sharply towards the equator; in some grains the colpi appear to be united at one pole only, while in others they appear to be united at both poles. Apocolpium diameter ca. 3.4 wide. Ora elongated longitudinally, often faintly delimited, length 6.8 pm, width 3.5 pm. Exine 1.4 /tm thick, thinning abruptly towards the apertures. Sexine distinctly striate. Lime 0.6 jtm wide supported by one to two rows of bacula. Striae 0.5 Itm wide. Tectal part of lirae 0.4 pm thick, infratectal baculate zone 0.6 Itm thick, and foot layer 0.4 [tm thick, infratectal baculate zone 0.6 pm thick, and. foot layer 0.4 Itm thick. Pollen very similar to thosc of Berlirrin species. Berliriiu airricirluta Benth. Herbarium material. Umuahia Okafor, FHI. colporoidate; peritreme-prolate (P pm, E 47.8 k3.5 pm). Sexine subtectate, striate. NPC: 345. Colpi 67.3 f4.2. pm long, Irm wide, with a medial constriction, margins distinct (2.5 f0.1 pm wide) membranes granulate, usually protruding beyond the surface of the grain in polar view. Apocolpium diameter ca. 6.4 t0.9 pm. Om usually only vaguely delimited. Exine ca. 2.1 pm thick. Sexine striate. Lirae 1.1 f 0.3 pm wide, simpli- to duplibaculate. Striae 0.7 & 0.1 pm wide, a few bacula sometimes occur within portions of the striae. Tectal part of lirae ca. 0.7 ko.1 pm thick, infratectal baculate layer 0.8 fo.l pm thick, and foot layer ca. 0.6 to.1 pm thick. Apart from the larger overall dimensions recorded here, the descriptions given by Smith (1964) and van Zinderen Bakker et al. (1959) agree with the present findings. B. cruibiuiin Bak. f. Herbarium material. Benin i958. Okoli, FHI. colporoidate; peritreme-prolate (P 79 L4.0 Itm, E 55.8 k2.6 pm). Sexine subtectate, striate. NPC: 345. (Apertural details similar to those in B. niirichtn.) Colpi 70.6 f3.4 pm long, 5.4 f0.8 pm wide. Apocolpium diameter pm. Ora vaguely delimited. Exine ca. 2.1 p i thick (details similar to those in B. nuricrrlafo). Lime 1.6 f0.2 /tin wide. Striae Itm wide. Tectal part of lirae ca. 0.6,mn thick, infratectal baculate zone 1.3 fo.1 /tm and foot layer 0.2 pm thick. B. gruridifloru (Vahl) Hutch. & Dalz. (PI. 2, Fig. 9). Herbarium material. Ibadan Keay, FHI. colpate to 3-colporoidate; peritrcme-prolate (P 64.5 k2.6 pn, E pm). Sexine subtectate, striate. NPC: 343, (345). (Apcrtural details similar to those in B. oirricir/ulo.) Colpi 52.6 k5.2 Itm long, pni wide. Apocolpium diameter /an. Ora vaguely delimited, not seen in all grains. G~nr~n 13.

10 154 -hf. A. Soioitriiiii Exine 1.6 pm thick. Sexine distinctly striate. Lirae 0.8 k0.2 pm wide; simpli- to duplibaculate, sometimes triplibaculate. Striae 0.9 k0.2 pm wide. Tectal part of h e 0.4 fo.l pm thick, infratectal baculate zone 0.7 fo.l pm, and foot layer 0.5 ko.1 pm thick. Apart from the smaller overall dimensions and exine thickness recorded here, the description by van Campo et al. (1960) agrees with the present findings. All three species of Berlitiia studied have similar pollen grains. Bmcliystegia citrycorria Harms (PI. 2, Figs ). Herbsriuni material. Oyo Adebusuyi, FHI. colp(or)ate; peritreme-prolate spheroidal (P 54. I k 2.5 pm, E 47.6 k4.6 pn). Sexine subtectate, reticulate NPC: 343, (345). Colpi 40.8 f2.5 pn long, ca pm wide for the most part, narrowing abruptly near the ends, membranes granulate. Apocolpium diameter 17.5 & 2.2 pm. Ora vaguely delimited and normally visible only in polar view. Exine 4.5 pm thick; Sexine very coarsely reticulate in the mesocolpia, finely reticulate in some parts of the apocolphia, the remaining parts consisting only of bacula, which are not arranged in any regular fashion and are sometimes, interconnected by very thin s-xinous strands. The apocolpia are thus sharply delimited from the mesocolpia. Muri pm wide, markedly curved, mostly duplibaculate, rarely simpli- or triplibaculate, discontinuous in parts, bacula mostly arranged marginally along the muri. Lumina 7.6k2.3 pm wide. Tectal part of muri 3.2k0.5 pm thick (thicker than both the baculate zone and foot layer together), infratectal baculate zone 0.8 k0.2 pm thick; some stouter bacula also occur at fairly regular though infrequent intervals the rounded tops of which project slightly beyond the surface of the grains; some of the bacula in the apocolpia appear to be branched. Foot layer 0.5 f 0.2 pm thick. B. nigerica Hoyle & A. P. D. Jones. Herbarium material. Ibadan 1964, Eyo, FHI. Pollzn grains isopolar, radially symmetrical; 3- colpate; peritreme-prolate spheroidal (P 39.2 k 1.9 pm, E 37.9 k3.2 pn). Sexine subtectate, reticulate. NPC: 343. The dimensions of the colpi couldmot be ascertained in this species. Exine 3.2 pm thick. Sexine pattern like B. eitryconm. Muri pni wide, markedly curved, (iraria 13 sirnpli- to duplibaculate, triplibaculate in places; bacula mostly arranged marginally along the muri, those in some parts of the apocolpia seem to branched. Lurnina 4.6 f 1.6 pm wide. The grains of B. eiirycoitia and B. iiigcrica are on the whole very similar, though those of the former are larger. Fossil grains similar to those of this genus were described by Clarke (1966; cf. Clarke et al. 1968) from the Upper Tertiary deposits in Nigeria. Dniiiclln ogca (Harms) Rolfe ex Holl. Herbarium material. Benin 1968, Olorunfemi, FHI. colporate; goniotreme, sides convex to straight-oblate spheroidal (P 41.8 f 1.7 pm, E 45.5 k 1.4 pm). Sexine pertectate. NPC: 345. Colpi 30.0 _+ 1.9 /cm long, 5.6 f0.7 pm wide, membranes granulate; Apocolpium diameter 6.4k 1.0 rim. Ora generally circular, sometimes slightly elongated transversely, diameter 9.5 prn, membranes with a coarse LO-pattern. Exine 1.7 Itm thick. Sexine tectate, LO-patterned. Tectum pm, infratectal baculate zone 0.2 ko.1 pm, and foot layer 0.7 k0.2 pm thick. D. oliceri (Rolfe) Hutch. & Dalz. (PI. 2, Figs ). Fresh material. Oyo 1968, Sowunrni 90. colporate; goniotreme, sides convex to straight-suboblate (P31.0kl.O/cm,E35.0k 1.5pn;KOH-treated grains were measured). Sexine subtectate, reticuloid. NPC: 345. Colpi united at the poles (colpi of immature grains free at the poles), width ca ,urn, narrowing gradually towards the ends and sharply constricted medially. Ora circular (length 9.9 f 1.4 pm, width 10.0 k 1.4 pm) surrounded by thin granulate margins (the ora are very distinct in KOH-treated grains, but often ill-displayed in acetolysed grains). Exine ca. 1.4 pm thick. Sexine faintly reticuloid. Tectal part of muri 0.5k0.1 pni, baculatc zone 0.3 ko.l pm, and foot layer 0.6 fo.l /cm thick. On the whole the pollen grains of this species became somewhat distorted and wrinkled during acetolysis. The pollen grains of D. ogea differ in detail from those of D. olireri: Mature grains of the former species are not syncolpate like those of the latter, the exine pattern of the former is an LO-pattern while that of the latter is the reverse. Also the grains of the

11 form-r do not seem to be adversely affected by acetolysis like those of the latter. Delortix regin (Boj. ex Hook) Raf. Fresh material. Ibadan 1968, Sowunmi 24. colporate; peritreme-prolate spheroidal (P 54.6k 1.6 pm, E pm). Sexine subtectate, reticulate. NPC: 345. Colpi 27.6 k 1.8 pm long, 4.4 k1.6 /cm wide medially, gradually tapering off towards the ends, colpi membranes finely reticulate. Ora elongated transversely (length 2.8 k0.6 pm, width 4.4 k 1.6 pm), not always clearly defined. Apocolpium diameter 27.2 k 1.8 Icm. Exine 5.3 /im thick. Scxine coarsely reticulate. Muri (2.4 k0.4 pm wid?), slightly curved, distinctly simplibaculate. Lumina (7.2 k 1.9 pn wide), supplied with 2-24 bacula which are much smaller than those below the muri and are usually concentrated in the centre. Tectal part of muri ca. 1.1 fo.l /cm thick, infratecal bscula mostly stout, their apical parts are swollen and usually projecting beyond the surface of the exine, height 4.4 k0.6 pm, basal -diameter 0.8 k0.2 /tm, apical diameter 2.3 k0.6 pm; smaller infratectal bacula 1.9 k0.4 pm high also occur, foot layer pm thick. Defariirrii riiicrocnrpirrii Guill k Perr. (PI. 2, Fig. 14; PI. 3, Fig. I). Herbarium material. Zaria 1950, Keay, FHI. coiporate, very rarely apparently 4-colporate; goniotreme, sides straight to convex-oblate spheroidal (P 33.0 f 1.8 pm, E 31.0 k 1.4 pm). Sexine subtectate, reticulate NPC: 345. Colpi 26.3 _+ 1.1 pm long, 2.5 k0.6 pm wide. Ora elongated longitudinally (length 7.3 kg.7, width 5.5 k0.7 pm). Apocolpium diamcter 10.3 k 1.1 pm. Exine 1.7 pm thick. Sexine reticulate. Reticulation heterobrochate, brochi finer in the apocolpia than in the mesocolpia. Muri (0.7 ko.1 pm wide) curved, distinctly simpli- to duplibaculate. Lumina 1.4 f0.4 pm wide. Tectal part of muri 0.4 k0.1 pm, baculate zone pm, and foot layer 0.6 ko.1 /rm thick. Disferiioiimrthrrs berifhnnrinrrirr Baill. Herbarium material. Calabx 1959, Latilo, FHI. colporate; lobate-prolate (P 33.0 pm, E 17.8 pm). Sexine subtectate, reticulate. NPC: 345. Polleii of Nigerinri plarrts: I 155 Colpi-28.4 pn long, ca. 1.8 pm wide, sometimes sharply constricted medially, with distinct margins 0.9 pm thick. Ora elongated longitudinally (3.6 pm long, 2.6 pm wide), often only faintly demarcated. Apocolpium diameter 4.8 pm. Exine 1.1 pm thick. Sexine minutely reticulate. Tectal part of muri 0.3 pm, baculate zone 0.3 pm, and foot layer 0.5 pm thick. Gossiceileronerrnrori balsariiiferrrrii (Verm.) Harms (PI. 3, Fig. 2). Herbarium material. Benin. Kennedy 554, FHI. Pollen grains isopolar, radially symmetrical; peritreme-oblate spheroidal (P ,urn, E 23.9 f 0.7 pm). Sexine subtectate, reticulate. NPC: 345. Colpi ca ko.9 pn long, 2.9 k0.3 pm wide. Ora comparatively large, slightly elongated longitudinally (length 5.5 k0.8 Icm, width 4.7 k0.7 pn). Apocolpium diameter 3.0 k0.3 pm.. Exine 1.4 pm thick. Sexine finely reticulate. Muri (0.4 ko.1 pi wide), sirnplibaculate. Lumina pm wide. Tectal part of muri 0.4 ko.1 pm, baculate zone 0.4 ko.1 pm, and foot layer 0.6 fo.l pm thick. Hynreriostegiu afzelii (Oliv.) Harms (PI. 3, Figs. 3-5). Herbarium material. Calabar 1959, Latilo, FHI. Pollen grains isopolar,radially symmetrical; 3-colporate (very rarely 2-colporate, viz. in 1.9% of the grains examined, or exceedingly rarely 4-colporate, in 0.5%); peritreme-subprolate (P 41.0 pm, E 30.4 pm). Sexine subtectate, striate. NPC: 345 (245, 445). Colpi 33.3 pm long, 2.8 pm wide, constricted medially, but sometimes of the same width throughout, margins conspicuously thickened (1.3 pm thick), membranes coarsely granulate. Ora mostly ill-defined and appear to be elongated longitudinally. Apocolpiuin diameter 9.2 pm, (2.4% of the grains examined proved to be syncolpate). Exine 1.7 pm thick. Sexine striate. Lirae 0.6 pm wide, simpli- or duplibaculate. Striae 0.4 pm wide, sometimes with bacula. Tectal part of lirae 0.5 pm thick, infratectal zone 0.5 pm, foot layer 0.5 pm thick, and endexine 0.2 pm thick. The Hq riuiostegin pollen grains bear a close resemblance to those of the Berliiiin and Isoberliriin species studied. Isoberliriin doka Craib & Stapf. (PI. 3, Fig. 6). Herbarium material. Zaria Dartner, FHI. colporate; peritreme-prolate (P 53.0 k3.6 pm, E 36.0 k2.9 pm). Sexine subtectate. NPC: 345. Grnrin 13

12 156 Al. A. Soivirririii Colpi long and narrow (length 43.1 k3.4 pm, width ca. 4.4k0.9 pm; sometimes with a medial constriction ( pm wide at the constriction), with conspicuous margins 2.0f0.2 /im thick, and granulate membranes. In polar view the colpal membranes protrude beyond the exine surface. Ora, longitudinally elongated (length pm, width 2.4 k0.3 rim), not always clearly delimited. Exine 2.7 pm thick. Sexine distinctly striate. Lirae (0.9 kc.1 pm wide), simpli- to duplibaculate. Striae 0.5 ko.1 /rm wide. Tectal part of muri 1.6 k0.5 pm, infratectal baculate zone 0.6 k0.2 pm and foot layer /cm thick. The close morphological similarity between Berliriin and Isobcrliriia is also reflected in their pollen morphology. Parkirisoriia acirleata Linn. (Larson and Lewis 1961, 1963). Herbarium material. Chkdra, Kanem, Tchad Maley. colporate (? very rarely 4-5); peritreme-subprolate (P 31.6 pm, E 25.4 pm). Sexine subtectate, reticulate. NPC: 345. CoIpi.25.4 /im long, ca. 2.0 pm wide medially, tapering off towards the ends, but in some grains sharply constricted medially; margins conspicuous (ca. 1.0 prn thick). Ora only faintly demarcated, apparently elongated longitudinally. Apocolpium diameter 8.7 pm. Exine 2.1 I'm thick, thinning sharply and abruptly towards the apertures. Sexinc reticulate, reticulation fainter and much finer towards and around the apertures. Muri 0.6 /rm wide, distinctly simpli- to duplibaculate. Lumina 1.3 pm wide, a very few bacula occur in some. Tectal part of muri 1.0 pm, infratectal baculate zone 0.7 pm, and foot layer 0.4 /im thick. Piliostigriin thoririirigii (Sch u m. ) Mi 1 ne-r ed hea d (PI. 3, Fig. 7). Herbarium material. Ibadan Emiriogbon, FHI. porate; peritreme-oblate spheroidal (P pm, E 34.4 k 116 pm). Sexine pertectate. NPC: 344. Pores?circular (ca. 4.8 k0.8 ~ ) pm. Exine 1.5 rim thick, gently undulating in parts. Sexine apparently tectate. Tectum 0.4 ko.l pm thick, provided with supratectal processes which seem to be of three types, viz. spinules, verrucae and pila, with spinules predominating. Spinules ca. 1.5f0.3 pm high, basal diameter 1.2k0.2 pm, verrucae ca pm high, basal diameter ca. 1.5 k0.4 Iim; density 29 per 15 pm*. Baculate zone 0.4 k0.2 pm, and foot layer 0.7 ko.1 pm thick. Van Zinderen-Bakker et al. (1959) reported the occurrence of tetra- and diporate grains, but none of these were encountered in the present study. Sicw-fzia nindagascarie/isis Desv. Herbarium material. Zaria 1965 Olorunfemi, FHI. colporate; peritreme-prolate (P 24.6 k2.2 pm, E 17.8 k 1.3 pm), Sexine subtectate. NPC: 345. The dimensions of colpi and ora could not be ascertained because of poor quality of the grains; the colpi were constricted medially, however. Apocolpium diameter ca. 1.7 k0.2 pm. Exine ca. 0.9 pm thick. Sexine negatively reticulate to vermiculate. Tectal part ca. 0.2 fo.l pm, baculate zone of same thickness, and foot layer 0.5 ko.1 rim thick. Cocli lospen iiqceae Coclilosperriiirrri plaiiclioiiii Hook f. (PI. 3, Figs. 8-9). Herbarium material. Borgu Macauley, FHI. colporoidate; peritreme-subprolate (P pm E 11.1 k0.8 pm). Sexine intectate? NPC: 345. Colpi ko.5 pm long. 0.9 pm wide, markedly constricted medially, united at the poles in a few grains (viz in 2% of the 500 grains examined). Ora not well defined. Apocolpium diameter 3.0 k0.4 pm. Exine 0.5 pm thick. Sexine apparently intectate, Plate 3. Fig. I. Defariiirir nricrocarpirnr (contd.) (x I 250) 3- colporate grain showing a colpus and an 0s. 2. Goss1~ei1erodendron balsanri/errim (x 1 250). note large 0s Hjnienostegia afzelii (x I 250) colporate grain; 4. 2-colporate grain; 5. 3-syncolporate grain. 6. Isoberlinia dokn (x 625) note 0s. 7. Piliasfignra rlronningii (x 1 250) Corlrlospernrrtnr planchonii (x I 250). 8. Non-syncolporate grain; 9. Gmrr.z 1.3 syncolporate grain Cornbrefrrnr glirtinositm (x 1 250). 10. Note 2 colpoid streaks on either side of central colpus; 11. Syncolporate grain. 12. Ternrirralia nracropfera (x 1 250). 13. T. superba (x I 250) note 2 colpoid streaks. 14. Verrionia corrferta (x 1 250) note large 0s V. frondosa (x 625). IS. Note winding, mural strand and puncta (white dots).

13 Polleii of Nigeriail planfs. I 157 Grnna 13

14 composed of pila and bacula, the apices of adjacent elements coalescent in some places. Coritbretncene Coriibretiirii gltrtiiiosrrrit Perr ex. DC. (PI. 3, Figs ). Herbarium material. Ilorin: Jebba Okafor & Daramola, FHI. colporate; goniotreme (Bsided), sides concave-subprolate (P [em, E 20.1 k1.0 pm). Sexine subtectate. NPC: 345. Apertures mostly faintly demarcated. Colpi ca f0.4 [ern long, ca: 1.2 f0.2 p-n wide, united at the poles in some grains. Ora elongated laterally (length ca. 4.1 kl.3 pm, width ca. 6.1 k0.7 pm). Alternating with the three colpi there are single colpoid streaks. Apocolpium diameter ca. 5.1 pm. Exine ca. 0.9 pn thick, thicker at the apertures (ca. 2.4 /cm thick). Sexine vermiculate to reticulate. Tcctal part of muri 0.3 ko.1 /ern (ca. 1.4kO.l pm at the apertures), infratectal baculate zone ca. 0.3 fo.0 pm (ca. 0.4fO.O [ern at the apertures), and foot layer 0.3 fo.l pm thick (ca. 0.6f0.1 /em thick at the apertures). Terinirialia aricertnioidcs Guill. & Perr. Herbarium material. Zaria Keay et al., FHI. colporate; goniotreme (6-sided), sides concavesubprolate (P 18.8 k0.8 pm, E 16.6f0.9 /em). Sexine subtectate, reticulate. NPC: 345. Colpi faintly delimited, generally narrow and comparatively long. Ora elongated laterally (length ca. 3.6 f0.5 pm, width ca. 5.0 k0.6 rim). Alternating with the three colpi there are single colpoid streaks. Exine ca. 1.0 /an thick. Sexine faintly and minutely reticulate. Tectal part of muri ca. 0.3 fo.0 pm, infratectal baculate zone ca. 0.2 fo.0 pm, and foot layer ca. 0.5 fo.l pm thick. T. glausccns Planch. ex Benth. Herbarium material. Ibadan Stanfield, FHI. colporate; goniotreme (6-sided), sides concavesubprolate (P 16.3 k0.6!em, E 13.4 k0.6 pm). Sexine subtectate?, NPC: 345. Colpi long, faintly delimited. Alternating with the three colpi there are single colpoid streaks. Ora not clearly delimited. Exine ca. 1.1!em thick. Sexine pattern often indistinct, but appearing to possess a fine OL-pattern. Tectal part ca. 0.3 ko.l /cm, baculatc zone ca /em, and foot layer ca. 0.6 ko.1 [em thick. T. macroptern Guill. & Perr. (PI: 3, Fig. 12). Herbarium material. Ghana Mann 9086, FHI. colporate; goniotreme (6-sided), sides concavesubprolate (P 19.4 fo.5 /em, E 15.6 fo.5 pm). Sexine subtectate, reticulate. NPC: 345. Apertures poorly displayed, hence no measurements could be made on thc available material. Colpi united at the poles in a few grains. Alternating with the three colpi there are single colpoid streaks. Exine ca. 1.2 pm thick. Sexine distinctly but finely reticulate. Muri 0.3 ko.l pm wide. Lumina 0.5 ko.1 pm wide. Tectal part of muri ca. 0.3 ko.1 pm, baculate zone pm, and foot layer 0.7 ko.l /em thick. T. sirperba Engl. & Diels (PI. 3, Fig. 13). Herbarium material. Olokemeji Kennedy 29, FHI. colporate; goniotreme (6-sided), sides concave-prolate spheroidal (P 18.2f0.6 pm, E 16.4k0.8 pm). Scxine subtectate? NPC: 345. Colpi ca f 1.1 pm long, ca. 0.6 ko.1 /mi wide. Alternating with the three colpi there are single colpoid streaks. Ora comparatively large, elongated transversely (length 3.8 k0.4 /em, width 4.5 k0.7 pm). Exine thickness was difficult to ascertain. Sexine pattern indistinct, but there seems to be a very faint OL-pat tern. The pollen grains of the five Combretaceous species studied on the whole resemble one another, collectively possessing a distinctive shape, apertural status, and sexine pattern. Coiitpositae Veritoitia conferfa Benth. (P. 3, Fig. 14). Herbarium material. Kumba Binuyo et al., FHI. colporate; goniotreme, sides convex-spheroidal (E 33.2 pm). Sexine subtectate, spinous. NPC: 345. Colpi ca pm long, margins wavy, ca. 3.8 /tm wide. Ora well defined, elongated laterally (length ca. 4.8 pm, width ca. 5.8 /em). Exine undulating, 1.5 pm thick between spines and 4.4 pm below spines. Sexine subtectate, provided with supratectal spines. Tectum comparatively thin (0.3 pm thick), densely punctate, traversed by anastomosing sexinous strands, which give rise to a very

15 roarse, pseudoreticulate pattern. Mural strands Minding, 3.5 Itm wide, provided with densely spaced jacula in 2 or more rows. Infratectal bacules beween spines 0.7 /tm long, foot layer 0.5 Icm thick. spines 3.2 pm long, basal diameter 1.8 pm, sharply 2ointed, sometimes with curved tips, regularly spaced along the mural strands, borne on raised portions of the exine, supported by stout, densely spaced bacula. Bacula below spines 3.6 /cm long, often branching and anastomosing towards their apices. T/. frottdosa Oliv. & Hiern (PI. 3, Figs ). Herbarium material. Calabar Onyeachusim, FHI. Pollen grains very similar to those of V. corlfertn (only the points of differences are mentioned here); goniotreme, sides straight to convex. Colpi ca. 27 pm long, ca. 4.7 wide medially, taperjng of towards the ends, membrane thin. Ora ca. 5.0 pm long, ca. 7.9 pm wide, may be slightly constricted medially. Exine 4.9 pm thick between spines and 5.8 pm below spines. Tectum 0.5 Icm thick. Mural strands 3.4 Icm wide. Infratectal bacula between spines 3.3 pm long, foot layer 0.7 pm and endexine 0.4 pm thick. Spines 3.9 pm long, basal diameter 1.7pm. Bacula below spines 4.2 pm long. Dipterocarpaceae hlottotes kerstitigii Gilg. Herbarium material. Ilorin Onochie, FHI. colporate; peritreme-oblate spheroidal (P 31.1 pm, E 31.E 31.8 pn). Sexine subtectate. NPC: 345. Colpi ca pm long, ca. 2.9 Icm wide medially, tapering off towards ends, margins distinct (1.7 pm thick), membranes thin. Ora elongated longitudinally, more rarely circular or slightly elongated laterally (length ca. 6.6 pm, width ca. 5.2 pm). Apocolpium diameter 6.0 /tm (a few grains were syncolpate). Exine 1.9 pm thick, thinning towards the apertures. Sexine reticulate, reticulation finer near to and around the apertures. Muri 0.8 pm wide, slightly curved in places, dupli-to triplibaculate, simplibaculate in places. Lumina 1.3 pm wide. Tectal part of muri 0.7 pm, infratectal baculate zone 0.6 pm, and foot layer 0.6 pm thick. Eberiaceae Diospjros CrassijJora Hiern. Herbarium material. 3apoba Amwiogbon. FHI. colporate, very rarely 4-colporate; goniotreme (sides convex) to peritreme-oblate spheroidal or prolate spheroidal (P 44.5 pm, E 46.2 pm or P 60.0 pm, E 53.1 pm respectively). Sexine subtectate. NPC: 345 (445). Colpi comparatively long (length ca pm, width ca. 2.5 pm), constricted medially, ends rounded and colpi often with a Ioopcd appearance thereabouts, margins granulate and distinct (ca..1.9 Itm thick). Ora large, elongated laterally (length 4.9 pm, width 17.1 pm) margins granulate and distinct, ca. 2.7 pm thick medially (near the colpi), tapering off abruptly distally, covered by very coarsely granulate membranes, which resemble opercula in polar view in some grains. Apocolpium diameter 10.7 pm. Exine ca. 1.2 pm thick (ca. 3.6 pm thick at the apertures), undulating. Sexine areolate, sexine islands mostly irregular in shape and size, the intervening channels traversed in several places by thin sexinous strands; bacula arranged marginally to the sexine islands. Tectum ca. 0.5 pni, infratectal baculate zone ca. 0.2 pm, foot layer ca. 0.5 pm thick, conspicuously thickened at the apertures (ca. 2.3,urn thick). Eitpltorbiaceae Eiiphorbia ka~iteriitiica Pax Herbarium material. Ibadan Okafor, FHI. colporate; peritreme to slightly goniotreme, sides convex-prolate (P 42.4k1.8 Icm, E 30.9k0.8 pm). Sexine subtectate. reticulate. NPC: 345. Colpi 34.5 k2.0 pm long, 3.1 ko.5 pm wide, sometimes constricted medially, margins conspicuously thickened ( pm medially, gradually narrowing towards the ends). Ora elongated longitudinally (length ca. 9.1 k1.5 pm, width ca. 5.6k0.6 pm). Apocolpium diameter 6.5 k0.9 pm. Exine 1.8 pm thick, thicker at the apertures (ca. 3.1 pm). Sexine minutely reticulate. Tectal part of muri 0.5f0.1 pm, baculate zone 0.8k0.1 pm, and foot layer 0.5 ko.1 pm thick. Hyriretiocardia acida-tul. Herbarium material. Ilorin Binuyo & Onyeachusim, FHI. colporate to 3-porate(?); pcritreme-oblate spheroidal (P 22.2 pm, E 25 pm). Sexine subtectate. NPC: 345 (344?). Colpi short (5.2 pm long, 2.3 Itm wide medially, tapering,off towards the ends), usually only faintly discernible; in many grains the large ora with the Crarra.13

16 160 hf. A. Sowirttttti coarse annuli obscure the colpi, in consequence such grains lappear porate. Ora conspicuously displayed, elongated longitudinally (length 3.5 pm, width 2.3 pm) annuli coarsely granulate (1.7,tun wide)..apocolpium diameter 16.2 pm. Exine ca. 1.3 pm thick. Sexine with a reticulate-like pattern. Muri simpli- to duplibaculate. Tectal part of muri ca. 0.5 pm, baculate zone 0.3 pm, and foot layer 0.5 pm thick. The observations of Bronckers et al. (1964) are in close agreement with those made here, except that no grains with four apertures were encountered in the present investigation. hfaacorutiga barteri Muell. Arg. Herbarium material. Cameroons Daramola, FHI. colporate; peritreme-oblate spheroidal (P 12.2 pm, E 12.3 pm). Sexine subtectate. NPC: 345. Colpi 8.7 p i long, 0.9pm wide medially, narrowing slightly towards ends. Ora markedly elongated laterally (length 0.7 pm, width 5.3 pm) distal ends indistinctly.demarcated, apparently with thin margins. Exine 0.8 pm thick, (1;7 pmthick at the apertures). Sexine minutely reticulate. Stratification indistinct. Afallotiis sirbrilntirs Muell. Arg. (PI. 4, Fig. 1). Fresh material. Ibadan Sowunmi, et al. 26. colporate; peripeme-oblate spheroidal (P 21.2 & 1.0,urn, E 21.8 fl.o pm). Sexine pertectate? NPC: 345. Colpi pm long, 2.2 f0.4 jrm wide, pontoperculate, opercula granulate. Ora only faintly demarcated, apparently circular. Apocolpium diameter 8.1 k1.1 pm. Exine 1.7 Icm thick, conspicuously thicker at the apertures (ca.,2.6 pm) where it seems ~o be more loosely arranged. Sexine apparently tectate, LO-pattern$d. Tecturn pm, infratectal baculate zone 0.3 k0.1 pm, foot layer 0.7 pm, endexine 0.3 pm thick: P/iyl/atrt/rirs discoides (Baill.) Muell Arg. Herbarium material: Oyo Keay; FHI. Pollen grains -isopolar, radially symmetrical; 3- colporate; peritreme-subprolate (P 22.0 & 1.3 pm, E 17.0 k0.6 pm). Sexine subtectate, reticulate. NPC: 345. Colpi 17.0k1.4 pm long, 0.8f0.1 pin wide, margins conspicuous ( pn thick medially, Grmm I t narrowing towards the ends). Ora circular or elongated longitudinally (length ca _0.5.pm, width ca. 3.4 f0.3 pm). Apocolpium diameter 5.0.fO.6 pm. Exine 1.3 pm thick. Sexine reticulate. Reticulum heterobrochate. Muri (0.5 k0.1 pm wide),.curved in places, simpli- to* duplibaculate. Lumina 1.0-kO.3 pm wide. Tectal part of muri 0.4 k0.1 pm, baculate zone 0.5 k0.1 pm, foot layer 0.4 k0,l pm thick. Ricitiodetidron Iieirdelotii (Baill.) Pierre ex Pax Herbarium material. Yaganbi Leonard 1147, FHI. colporate; oblate-prolate (P 36.3 ltm, E 23.8 pm). Sexine subtectate. NPC: 345. Colpi very long (length 34.2 pm) with conspicuous margins (ca. 2.5 pm thick). Ora elongated longitudinally (its dimensions could not be ascertained). Apocolpium diameter ca. 7.0 pm. Exine 2.0 Itm thick, stratification very distinct. Sexine reticulate. Muri (0.6 pm wide) simpli- to duplibaculate. Lumina 0.7 pm wide. Tectal part of muri 0.6 pm, baculate zone 0.5 pn, foot layer 0.7 pm, and endexine 0.2 Itm thick. Spotidiatrthris preirssii Engl. var. preirssii (PI. 4, Figs. 2-3). Herbarium material. Onitsha Jones 2131, FHI. colporate; peritreme-subprolate (93.5'3, of the grains examined) or prolate (6.50/0) (P 17.1 pm, E 20.3 pn or P 21.2 pm, E 14.4 pm, respectively). Sexine subtectate. NPC: 345. Colpi 15.6 pm long, 1.8 pm wide (constricted medially in some grains), margins 1.4 pm thick (0.9 jtm in prolate grains), narrowing abruptly distally. Ora markedly elongated laterally (length 1.6 pn, width 5.4 pm). Apocolpium diameter 3.1 pm. Exine 1.2 pm thick. Sexine' minutely reticulate..tech1 part of muri 0.3 pm, baculate zone 0.3 pm, and foot layer 0.6 pm thick Uapaca escrrleitta A. Chev. ex AubrCv. & Leindri. Herbarium material. Benin: Sapoba. Kennedy 1895, FHI. colporate; goniotreme, sides convex-oblate spheroidal (P ca. 24.6k0.6 pm, E 26.4fl.0 pm). Sexine subtectate. NPC: 345. Apertures consirt of an outer colpal part, and an inner, transversely elongated, oral part. (No measurements could be made due to the poor quality of the material available.)

17 Plure 4. Fig. I. Afuallofrrs srrbrrlofrrs ( x I 250) note opercula. 4-pororate grains; / I. (x SOO) 5-pororate grain; 12. (x I 000) 2-3. Spondianrhrrs prerrssii (x I 250). 2. Prolate grain; 4-pororate grain Ircingio gabonensis (x 1 250) Subprolate grain. 4. Uupaca palrrdosu (x I 250) (1. Note large 0s and narrow colpus. IS. h'lainedoxu gabonensis staudfii ( x I 250) 6. Note groups of pila (dark dots)at angles (x I 250) note large 0s and narrow colpus Combreof brochi. 7. Oxjfenunrheru ubyssinica (x I 250) Sym- fodenrlron rnncrocurprtnr (x 625). 16. Non-syncolpate grain; phonifl globrtlyera. 8. (x I 000) 3-pororate grain; (x 625) 19. syncolpnte grain.,

18 Exinc ca. 1.9 /em thick (including processes), pouting at the aperturcs where it is more loosely arranged. Sexinc with an irregularly reticulate pattern formed by isolated pila as well as groups of pila. hlinute processes occur within the lumina. Height of pila ca. 0.7 pm, capita diameter ca. 0.8 I'm. Foot layer ca. 0.4 [em. U. giriiieeiisis Muell. Arg. Herbarium material Calabar,1953. Onochie, FHI. colporate; goniotremn, sides convex-suboblate (P 19.4 pm, E 23.5 pm). Sexine subtectatz. NPC: 345. Colpi long (not clearly defined). Ora markedly elongated laterally (length 2.8 pm, width 9.0 /em), distal ends not clcsrly defined. Apparently operculate. Exine 1.2 pm thick. Sexine with a reticulate-like pattern, muri multibaculate. Tectal part of muri 0.3 pm, bsculate zone 0.3 pm, and foot layer 0.6 pm thick. U. polirdosa Aubrkv. & Lemdri (PI.,4, Fig. 4). Herbarium material. Benin Charter, FHI. colporate; goniotreme, sides convex or straight-suboblate (P 20.6 ko.9 pm, E 23.4 k 1.2 pm). Sexine subtectate? NPC: 345. Colpi faintly delimited (length ca f 1.9 pm, width CB. 1.0 k0.2 pn). Ora elongated transversely (length 3.1 f0.3,urn, width 5.8 i 1.0,mi, slightly constricted medially). Exine 1.6 pm thick (including processes), pouting at the apxtures, where it is more loosely arranged. Sexine with a reticulate pattern as in U. esctikntn. Muri (0.9 k0.2 pm wide), discontinuous over most areas. Lumina (1.3 k0.4 pm wide), provided with groups of small pila. Height of pila 0.8i0.1 pm, basal diameter ca pm, capita diameter ca. 0.5 ko.1 pm. Foot layer ca. 0.8 k0.2 pm. U. statidtii Pax (PI. 4, Figs. 5-6). Herbarium material. Ogoja Latilo, FHI. colporate; goniotreme, sides straight or convexoblate spheroidal. (P 20.9 f 1.2 /em, E 21.6 k 1.4 [tm). Sexine subtectate? NPC: 345. Colpi faintly delimited (length ca. 9.3 k0.7 I'm, width ca. 0.8k0.2 gm, tapering off towards the ends. Ora elongated transversely (length 3.9 i0.4 {em, width 7.1 k0.8 [em). Graiia 13 Exine 1.3 /em thick, thicker at apertures (ca. 2.2 pm) where it pouts and is more loosely arranged. Sexine with a reticulate pattern as in U. escrilerrta. Muri (0.9 k0.2 /em wide), discontinuous in parts. Lumina (1.2 k0.4pm wide) provided with some small processes (pila?). Tectal part of muri 0.4 kc.1 pm, baculate zone 0.3 ko.1 /mi, foot layer 0.6 AO.1!em thick (ca. 1.5 i0.2 pm at apertures). U. togoemis Pax Herbarium material; Zaria Jackson 146, FHI. colporate, very rarely 4-colporate; peritreme or goniotreme, sides convex-oblate spheroidal (P 19.6 f 0.6 pm, E 20.8 k0.7 /em). Sexine subtectate? NPC: 345 (445). Colpi ca k 1.2 pm long, ca. 0.6 io.l,mi wide in the middle, tapering away towards the ends. Ora markedly elongated transversely (length 3.2 k0.4 itm, width 7.4 k0.4 pm), constricted medially. Exine ca. 1.7 pm thick, (including processes), thicker at the apertures (ca. 3.5 pm) where it pouts and is more loosely arranged. Sexine with a reticulate pattern as in U. cscrrlento. Muri (0.8 ko.1 pm wide), discontinuous in places. Lumina 1.0 kc.2,mi wide. Pila 0.7 ko.1 pm high (2.0 k0.2 at the apertures), basal diameter 0.2 ko.1 pm, capita diameter 0.4 ko.1 /em. Foot layer /tm thick. The pollen grains of all four species of Unpaca studied arc similar on the whole.. Flncourtinccne Oticobn spitiosn Forsk. Fresh material. Ibadan Sowunmi et al. 40. colporate; peritreme or slightly goniotreme, sides convex or straight-prolate spheroidal (P 26.5 k0.5 pm, E 24.4 k0.7 pm). Sexine subtectate, reticulate. NPC: 345. Colpi 20.7 k 1.2!em long, 2.6 f0.3 Itm wide, membranes finely granular or smooth. Ora elongated transvsrsely (length 2.1 k0.3 pni width 9.3 k0.4 pm, tapxing off abruptly towards the ends), with thin granulate margins. Apocolpium diameter 7.7 k0.8!em. Exine 1.2 pn thick (2.0 Icm thick at the apertures). Sexine reticulate. Reticulum heterobrochate, becoming finer towards and around the apertures. Muri (0.7 i0.2 /em wide), simpli- to dublibaculate. Lumina 1.1 f0.3 pm wide. Tectal part of muri 0.4k0.1 pm,

19 Polleri of Nigeriati plants. Z.163 Downloaded by [ ] at 23:10 21 November 2017 baculate zone 0.2 ko.1 pm. and foot layer 0.6 ko.1 pm thick. Bronckers (1967) recognized two different types of pollen grains in Oiicoba spiriosa viz. subprolate and oblate spheroidal. The present author did not find such a dimorphism in her material, the shape of the pollen. grains being described as prolate spheroidal. The shape variation that did occur among the examined pollen grains was not considered sufficiently striking to warrant their being classified as two, or more, distinct types. Graiiiirieae Oxyterrarithera abyssitiica Linn. (PI. 4, Fig. 7). Herbarium material. Zaria Lapai, FHI. Pollen grains heteropolar, bilateral; 1-porate; oblate spheroidal (P 42.3 pm, E 44 um). Sexine tectate? NPC: 134. Pore circular (diameter 3.4 pm) with a distinct, granulate annulus (2.8 pm wide). Exine 0.9 /cm thick, undulating. Pattern faint, apparently an LO-pattern, stratification indistinct. Guttilerne Syniphoriia globiilifcra Linn. f. (PI. 4, Figs. 8-12). Herbarium material..calabar Binuyo, FHI. Pollen grains isopolar, rad,ially symmetrical; 4- pororate or 4-pororoidate, rarely 5-pororate or 5- pororoidatc (in 6.5% of the 110 grains examined), very rarely 3-pororate or 3-pororoidate (3 %); goniotreme (4-, 5- or 3-sided, respectively; sides convex or straight)-suboblate (in 4-pororate grains) (P pm, E 45.0k2.6 /mi). Sexine subtectate. NPC: 444,446 (544, 546; 344, 346). Apertures consist of an outer, circular, poral part (6.6 ko.8 x 6.7 k0.5) pni, whose margins have numerous cracks, and an inner oral part which is not distinctly visible in all grains. Apoporium diameter 28.6 pm. Exine ca. 3.7 pm thick, (ca. 5.8 pn thick at and near the apertures), stratification indistinct. Sexine vermiculate, channels narrow, sometimes anastomosing or traversed by narrow sexinous strips, bacula arranged marginally to these channels; sexine islands punctate. This species has trimorphic pollen, the three types of grains differing from one another with regard to aperture number, size and shape. The occurrence of compound apertures (viz. pores and ora) in Syrilphoriia globidifern earlier pointed out by Erdtman (1952, 1966) is confirmed 1 I by the present investigation. As indicated by Erdtman (ibid.) the ora.were not always distinctly delimited.. He described the pollen grains of this species as being (3-)Caperturate (poratc-pororoidate) and those of S. globidifera var. gaboilerisis as 415?aper- turate (porate-pororoidate). The two subspecies, however, are now considered synonymous (Hutchinson et al., ), hence Erdtman s (ibid.) observations are nevertheless in agreement with those of the present author who describes the grains as being (3-)4(-5) porate-pororoidate. Ircitigiaceae Ircirigia gabonemis (Aubry-Lecomte ex O Rorke) Baill. (PI. 4, Figs ). Fresh material. lbadan Sowunmi et al. 32. colporate; goniotremc, sides concave or straightsuboblate (P 20.6 f 1.0 pm, E 23.8 i-1.0 pm). Sexine subtectate, reticulate. NPC: 345. Colpi ca k0.5 pm long, a p n wide. Ora comparatively large, elongated longitudinally (length 8.0 k0.3 pm, width 3.5 k0.4 pm), margins conspicuous (2.7 k0.3 pm thick).. Apocolpium diameter pm. Exine 1.5 Itm thick. Sexine finely striato-reticulate. Lirae supported by a row of bacula. Tectal part of muri 0.6 ko.1 pm, infratectal baculate zone 0.2 ko.1 pm, and foot layer 0.7 k0.2 pm thick.. Z. gratidijlorn (Engl.) Engl. Herbarium material. Ogoja Iones, FHI. Pollen grains very similar to I. gaborietisis (only the slight differences are mentioned here): P 16.8 pm, E 20.6 pm. Colpi ca pm long, ca. 0.7 pm wide, narrower towards the ends. Ora ca. 4.6,mi long, ca. 5.4 pm wide, margins 2.3 pm thick. Exine 1.4 pm thick. Sexine finely and minutely reticulate, granulate around apertures where it is less dense. Tectal part of muri 0.4 pm, infratectal baculate zone 0.2 pm, foot layer 0.6,urn, and endexine 0.2 pm thick. Klaiiiedoxa gaborietisis Pierre ex Engl. var. oblotigifolia Engl. (P. 4, Fig. 15). Herbarium material. Benin: Sapoba. Kennedy 302, FHI. colporate; goniotreme, sides straight or concave-suboblate (P 13.8 k0.6 pm, E 16.8 k0.7 pm). Sexine subtectate, reticulate. NPC: 345. Colpi ca. 9.0 k0.8 pm long, ca 0.9 f0.2 pm wide. Grarin.13

20 164 M. A. Soiviinnii Ora elongated longitudinally, (length 5.3 k0.7 pm, width 2.0 f0.3 pm), margins conspicuous (2.0 f0.3 pm thick). Apocolpium diameter 10.8 k 1.8,inn. Exine thickness was difficult to ascertain, stratification indistinct. Sexine finely reticulate to striatoreticulate. The pollen grains of K. gabonensis, on the whole, are, closely similar to those of Iroirigia gaborierisis and I. grmidifora. Both genera also have several morphological features in common (cf. Keay et al. 1964). Lecit Iipfaceae Coiiibretodeiidron iiiacrocarpiitii (P. Beauv.) Keay (PI. 4, Figs ). Herbarium material. Ogoja: Ikom Latilo & Olorunfemi, FHI. colpate (syncolpate); peritreme (P 48.2 k2.5 pm, E 36.1 k 1.2 pm). Sexine subtectate. NPC: 343. Colpi united, undulating, narrow over most of their length (3.0k0.5 pm wide) with a prominent medial bul$e (ca. 6.7 k0.8 pm wide), margins very conspicuously thickened (2.9 f0.6 pm), and ever more so at and near the poles (5.1 pm), here projecting above the general exine surfacc, membranes granulate. Exine gently undulating, ca. 1.8 /tm thick, considerably thickened at the poles (5.1 pm thick) where it is also more coarse. Sexinous thickening at the poles plano-convex, the convex surface facing outwards. Sexine areolate for the most part, scrobiculate in plaies. Sexine islands mostly polygonal, sometimes irregular, with marginal bacula. Tectum 0.7 ko.1 pm (3.3 k0.6 Itm at the poles), baculatc zone 0.7 ko.1 pm (0.9 k0.2,um at the poles) and foot layer 0.4 ko.1 pm ( pm thick at the poles). These grains are very distinctive and belong to the Planclionia-type describcd by Erdtman (1952, 1966). They are completely unlike those of Coriibretiini. Conibretodendron is so named because its fruits resemble those of Conibretiini. hlalcaceae Azarizn gnrckeuria (F. Hoffm.) Exell & Hillcoat (PI. 5, Fig. 1). Herbarium material. Gonibe 1968, FHI. Pollen grains isopolar, radially symmetrical; polyporate; pantotreme-spheroidal (diameter 105 pm). Sexine tectate. NPC: 764. Pores (more than 20) circular, (diameter 6.6 pm), each surrounded by a distinct annu!us, (4.4 ltm wide). Exine 5.0 pm thick (6.6,um at pores). Sexine spinose. Spines (9.2 prn long, basal diameter 5.1 pm), neck usually curved, tip blunt, density 4.6 per 22.5!tm*; borne on raised parts of the exine and supported.by very stout, densely spaced bacula. Bacula below spines 6.4 prn high and 1.0 pm in diameter, tops slightly swollen, adjacent bacula usually coalescent to form the thin tectum-on which the spines rest; often branched near the apices. Tectum 0.4 pm, with minute perforations in places, bacula (between spines) 2.6pm long, foot layer 1.6 pm (4.2 Jim at pores), and endexine 0.4 pm thick. Bacula appear to extend into the foot layer, sometimes even into the endexine. Hibiscus tiliaceirs Linn. (PI. 5, Figs. 2-6). Herbarium material. Yenagoa: Akassa Ossain, FHI. Pollen grains isopolar, radially symmetrical; polyporate; pantotreme-spheroidal ( k6.6 x pm). Sexine intectate? (-subtectate). NPC: 764. Pores (more than 30) nearly isodiametric (6.1 f0.5 x 6.5 k0.6) pm, bordered by conspicuously thickened, granulate annuli (3.5 t0.6 pm thick). Exine 3.8 pm thick, gently undulating. Sexine provided with pila, bacula, and polymorphic, apparently supratectal spines. Spines (16.4 f 1.0 pm long, basal diameter 6.2 k0.7 pm), mostly stout with distinct, narrow necks and pointed tips, rooted by means of bacula in slightly raised parts of the exine, occasionally branching once or twice (branches comparatively short); some spines are very blunt, without any distinct, narrow neck (length 8.9 k0.8 pm, basal diameter 6.6 k0.7 pm); a third type of spine, smaller with a distinct, narrow neck and pointed tip also occurs (length ca. 6.4 ko.8,mi, basal diameter ca. 2.5 k0.4 pm). Density of spines 1 per 15 pmz. Very densely spaced on the grains are pila and bacula (1.4k0.4 pm hige) and the capita of some adjacent pila coalesce to form a thin tcctum in such areas; the bacula below the stout spines are Plate 5. Fig. I. Azanra garcckeana (x 250) Hibiscus (x 1 250) 5-colporate grain Acncia senegal. 10. tiliaceirs. 2. (x 500) note distinct annulus around each pore; (x 1 000) polyad; 11. (x 1250) single grain showing a pore 3. (x 625) optical cross-section; 4-6 (x 625) branched and at the proximal pole A. sicberiana (x 625). 12. single unbranched spines. 7. Entnndrophragnta angolense (x 1 250) grain; 13. polyad. 14. Aubrerillea kerstingii (x I 250). IS. Calnote Y-shaped streak. 8. E. trtile (x l 250). 9. Khaya irorensis pocalyx caii/iflorirs (x l 250) octad. Grarra 13

21 Pollen of Nigerim plnrits;. I 165 Groiio 13

22 166 M. A. Soivittiriii larger than those over the general surface of the grains (height 2.4 k0.8 pm, diameter 0.9 k0.2 pm). Foot layer 2.4 pm thick. Erdtman (1952, 1966) in a very brief reference to the pollen of H. tilinceirs gave thc length of the spines as being about 33 pm, but their lengths on the present material studied were only about half that value. At present, this wide disparity is hard to resolve, nor did he report finding any branched spines. Aieliacene Eritaridrop?iragiiio nrigolerise (Welw.) C. DC. (Pi. 5, Fig. 7). Herbarium material. Ibadan Ogan, c u r Pollen grains isopolar, radially symmetrical; 4- colporate, rarely 3-colporate (viz. in 2.1 % of the 330 grains examined); peritreme to slightly goniotreme (4lsided, sides convex)-oblate spheroidal (P 25.3 If: 1.1 /em) E 26.5 f 1.2 pi). Sexine subtectate. NPCi 445 (345). Colpi 12.5 f 1.8 [ern long, pm wide; in a few grains three of the four colpi were united by exinous streaks (this appears to be a strange case of incomplete syncolpatism), in even fewer grains all four colpi were united. Ora elongated transversely (length 2.6 k0.5 /em, width 3.4 ko.3 /ern) margins conspicuous (ca. 0.7 fo.l!em thick). Apocolpium diameter 10.8 f 1.2 pm. Exine ca. 1.5!em thick (2.0 pm at the apertures). Sexine very finely and faintly OL-patterned. Tectal part 0.4 fo.1 pn, infratectal baculate zone 0.2 fo.0 /em, and foot layer 0.9 ko.1 pm thick. E. caridollei Harms. Herbarium material. Ondo: Akure Keay, FHI. Pollen grains isopolar, radially symmetrical; 4- colporate; peritreme to slightly goniotreme (4-sided; sides convex tostraight)-prolatespheroidal (P28.6 f 2.2*pm, E 26.4 k1.8 {tm). Sexine subtectate. NPC: 445. Colpi 20.5 k 1.5pm long, 0.9 fo.1!ern wide, may be slightly constricted medially, margins ca. 3.6 k0.2 ycm wide medially, sharply tapering off towards the ends. Ora elongated transversely, (length I.7 f0.3 inn, width 5.7 k0.7,tern). Apocolpiuni diameter 11.9 k 1.4 /em. Exine ca. 1.9 /ern thick (ca. 3.3 pm at the apertures). Sexine faintly and finely OL-patterned, stratification indistinct. drmia ij E. utile (Dawe & Sprague) Sprague (PI. 5, Fig. 8). Herbarium material. Ondo: Akure Jones 136, FHI. Pollen grains isopolar, radially symmetrical; 4- colporate; goniotreme (Csided, sides convex) to peritreme-oblate spheroidal (P ca k 1.2!em, E ca. 26.7k.1.4 pm). Sexine subtectate. NPC: 445. Colpi ca k1.2 pm long, ca. 1.0 f0.3 wide at the middle, tapering off towards the ends. Ora elongated transversely (length ca. 2.7 f0.5 /em, width ca. 3.2 k0.3!em), with distinct margins. Exine ca. 1.6 pm thick (2.8!em thick at the apertures). Sexine finely OL-patterned. Tectum ca. 0.3 pn, bsculate zone ca. 0.2, foot layer ca. 0.8 /em, endexine ca. 0.3!em thick. The pollen grains of all three species of Eiitaridroplrrugriia studied are similar. Kliayu icoretisis A. Chev. (Pi. 5, Fig. 9). Herbarium material. Ijebu: Omo Adesia, FHI. Pollen grains isopolar, radially symmetrical; 4- colporate, occasionally 5-colporate; goniotreme (4- sided, sides convex or concave) -prolate spheroidal (P 31.8 k2.6 /em, E 31.3 k2.4 pm). Sexine subtectate. NPC: 445 (545). Colpi 16.8 f 1.9 pm long, 1.0 k0.2 prn -wide. Ora nearly isodiametric (2.7 k0.6 x 2.8 f0.3) pm, with distinct margins (ca. 0.8 ko.l pm thick). Apocolpium diameter ca /em. Exine ca. 1.1!em thick (ca. 2.5 Irm at the apertures). Sexine minutely reticulate. Tectal part ca. 0.3!em, baculate zone ca. 0.2 /em, and foot layer ca. 0.6 pm thick. Locou tricliilioides Harms. Herbarium material. Ijebu: Omo Akinduro, FHI. Pollen grains isopolar, radially symmetrical; 4- colporate, occasionally 5-colporate; goniotreme (4- sided, sides convex to straight)-subprolate (P 25.4 k 1.2 pm, E 21.5k1.1 pm). Sexine subtectate. NPC: 445 (545). Colpi 19.0 f 1.8 /ern long, 1.1 k0.2 [ern wide. Ora elongated transversely (length 1.9 k0.3 pm, width 5.9 f0.5 pm). Apocolpium diameter ca. 7.4 f0.7 /em. Exine: thickness and stratification could not be ascertained. Sexine OL-patterned. Tricliilia prieuriana A. Juss. Herbarium material. Ibadan: Gambari Onochie & de Witt 688, FHI. Pollen grains isopolar, radially symmetrical; 4-

23 colporate, goniotreme (4-sided, sides straight or convex)-prolate spheroidal (P 26.3 f2.0 pm, E 23.4 rfr 2.0 pm). Sexine subtectate? NPC: 445. Colpi 16.8 f 1.1 prn long, 0.7 ko.1 prn wide, margins conspicuous (1.7 k0.2 yim thick). Ora nearly isodiametric (3.1 f0.3 x 3.2 k0.4 Jim). Exine: thickness. and stratification could not be ascertained. Sexine pattern indistinct. On the whole, the pollen grains of all the five Meliaceous genera studied are strikingly. similar, especially with regard to apertural status, colpus width, and sexine pattern. Mitiiosaceae Acacia dlrdgeotii Craib ex Holl. Herbarium material. Bornu Jackson 593, FHI. Pollen grains clustered in polyads with 16 grains in each, in a regular arrangement: 8 grains in the centre arranged four and four in two planes, the planes lying directly one above the other; and these eight are surrounded in turn by eight peripheral grains; individual grains 3-porate or 4-porate; the polyad rounded tetragonal in shape, the individual grains tetragonal or polygonal, with smooth and uninterrupted outlines (polyad 47.3 rfr 1.7 x 44.7 f 1.3 pm, individual grains 14.2 f 1.0 x 15.6 rfro.8 Iim). Sexine pertectate? NPC: 344 (444). Apertures consist of faintly delimited, nearly isodiametric pores covered by granulate membranes and situated immediately below the exine surface. Exine ca. 0.9 pm thick on the distal face, much thinner on the proximal face. Sexine pattern very faint and indistinct, apparently an OL-pattern. A. nrarcrotliyrsa Harms. Herbarium material. Katsina Keay, FHI. Pollen grains clustered in polyads with 16 grains in each, pollen arranged as in A. didgeotii; individual grains are apparently 3-colporate; the polyad rounded tetragonal in shape, individual grains tetragonal, sides convex to straight, surface interrupted by the pores (polyad 49.2 f3.5 x 42.5 k3.6 pm, individual grains 17.9 k0.4 pn x 15.1 k0.2 am). Sexine pcrtectate? NPC: 345. Colpi united (forming a Y-shaped furrow). Ora distinct. Exine 1.7 pm thick on the distal face and thinning very abruptly towards the apertures; much thinner on the proximal face. Sexine pattern indistinct, apparently an OL-pattern. Tectum 0.4f0.1 pm, rami- Pollen of Nigerian plants.. I 167 baculate in parts,. baculate zone 0.7 k0.3 pm, and foot layer 0.6 ko.1 pm thick. In a short description of the pollen of A. niurcrothyrsa, Sorsa (1969) did not mention the apertural status. According to Guinet (l969), the sexine is reticulate. A. ruddiatia Savi. Herbarium material. Bornu kern 3781, FHI. Pollen clustered in polyads with 16 grains each, pollen arranged as in A. didgeorii; individual grains 3colporate; the polyad rounded tetragonal in shape, individual grains tetragonal, sides convex to straight, outline undulating in places (polyad 48.2 k2.4 x 44.2 k2.6 pm, individual grains x 15.7 f 1.1 rim). Sexine pertectate. NPC: 345. Colpi united as in A. niarcrotliyrsa. Ora distinct. Exine ca. 1.4 prn thick on the distal surface and thinning sharply towards the apcrtures, much thinner on the proximal face. Sexine pattern obscure (LOpattern?). Tectum ca. 0.2 jim, ramibaculate in parts, baculate zone ca. 0.4 pm, foot layer ca. 0.6 pm, and nexine ca. 0.2 pm thick. The present observations agree closely'with those of Guinet (1969) and Sorsa (1969). A. setiegal (Linn.) Willd. (PI. 5, Figs ). Fresh material. Ibadan Sowunmi et al. 12. Pollen grains clustered in polyads with 16 grains in each, arranged as in A. hdgeotii; individual grains 5-porate, sometimes apparently 4-porate; the polyad rounded, tetragonal in shape, individual grains tetragonal, sides straight, concave, or convex, smooth and uninterrupted in outline (polyad 47.6 f 1.8 x' pm, individual grains 17.1 f 1.0 x rim). Sexine pertectate. Pores circular or elongated longitudinally (diameter 3.4 f0.5 pm), membranes granulate, four of the pores are meridional (or may be slightly subequatorial) while the fifth is situated at or near the proximal pole (the poles are easily distinguished since the grains are compound). Exine ca. 1.4 Iim thick on the distal face, much thinner on the proximal face, pouting slightly at the pores (in the grains lying in the centre of the polyad), stratification indistinct.. Sexine pattern indistinct (LO-pattern?). The occurrence of a pore at the proximal pole in addition to the four meridional pores, an unusual arrangement of apertures, was pointed out earlier by van Zinderen Bakken et al. (1959). Gram I3

24 168 Af. A. So~vwinii A. scpl Del. llerbarium material. Jos Plateau Faithful, FHI. Pollen grains clustered in polyads with 16 grains in each, arrangcd as in A. dirdgeoni; individual grains 3- colporate; the polyad rounded tetragonal to almost circular in shape, individual grains tetragonal, sides convex to straight, outlines undulating in places, surface interrupted by pores (polyad x 44.9 f 1.8 pm). Sexinc subtectate. NPC: 345. Apertures as in A. niarcrotlijrsa. Exine 1.6pni thick on the distal face, much thinner on the proximal face, thinning very abruptly towards the apertures. Sexine pattern rather obscure, but seems to be an LO-pattern and a negatively reticuloid one. Tcctal part 0.4k0.1 Iim thick, baculatc zone yim thick, and foot layer 0.5 fo.l Iim thick. Guinet (1969) described the exinc as being reticulate but this is at variance with the present observations. A. siebcrintin var. cillusn A. Chev. (PI. 5, Figs ). Herbarium material. Bornu Daramola, FHI. Pollen clustered in polyads with 16 grains in each, arranged as in A. dirdgeoni; individual grains 3-colporatc; the polyad rounded tetragonal in shape, individual grains tetragonal. sides convex to straight, surface interrupted by pores (polyad 49.8 f 1.4 x 46.0 k2.6 pm, individual gains 18.8 f0.7 x 16.4 f 1.0 pm). Sexine pcrtectate. NPC: 345. Apcrtures as in A. niorcroflijrsa Exine 1.5 Irm thick or the distal face, much thinner on the proximal face. Sexine with a distinct LO-pattern. Tectum pm thick, ramibaculate in parts, baculate zone 0.4f0.1 /im thick, and foot layer /im thick. Aubrecillen kerstirigii (Harms) Pelleg. (PI. 5, Fig. 14). Herbarium material. Sardauna province Latilo & Daramola, FHI. colporatc; goniotreme, sides convex-prolate (P 39.6,rim, E 26.6 pm). Sexine subtectate. NPC: 345. Colpi united at the poles, width 0.8 /rm, slightly wider at the ends, margins conspicuous (1.1 pm thick) Ora faintly demarcated, appear to be elongated longitudinally, membranes distinct, may project beyond surface of grain. Exine 1.3 pm thick. Scxine with an irregular OLpattern which may become reticulate in places. Tectal part 0.4 pm thick, baculate zone 0.5 pm, and foot layer 0.4 pm thick. It is rather surprising that in the short description of these grains given by Sorsa (1969) their syncolpate status is not mentioned. Calpocdyx caiilijlorrrs lloyle (PI. 5, Fig. 15; PI. 6, Fig. 1). Herbarium material. Ogoja: Ikom FHI. Pollen grains united in octads, pollen arrangement apparently irregular, sometimes 5 and 3 in 2 planes (commonest), or 4 and 4:or 6 and 2; individual grains 3-porate, rarely 4-poratc; polyad shape variable, individual grains goniotreme, sides straight or convex (triangular or tetrangular) (polyad 35.2 x 31.6 pm). Sexine subtectate. NPC: 344 (444). Pores with annuli and granulate membranes. Exine 1.4 /tm thick, thicker at the pores. Sexine very finely reticulate. Tectal part, baculate zone and foot layer each 0.4 Iim, endexine 0.2 pm thick. C.diriklvgei Harms. Herbarium material. Cameroons Binuyo & Daramola, FHI. Pollen grains united in octads, pollen arrangement mostly in 4 and 4 in 2 planes, or sometimes 6 and 2, or even in 3 plancs of 3, 2 and 3, individual grains 3-porate; polyad rounded tetragonal or elongated, individual grains rounded triangular or tetrangular (polyad 44.9 x 32.5 /im or 50 x 31.2 pm; individual grains 23.4 x 17.1 pm). Sexine tectatc. NPC: Pores with annuli (ca. 1.4 Iim thick) and granulate membranes. Exine 1.4 Irm thick, thicker at pores. Sexine punctate. (Other details as in C. caitliflorirs.) Diclirostaclip cirieren (Linn.) Wight & Am. (P. 6, Figs. 2-7). Herbarium material. Zaria Latilo FHI. Pollen grains isopolar to subisopolar radially sym- Plate 6. Fig. 1. Calpoca1j.r rait1ijlor;ts (contd.)' ( x'i 250) octad Dichrosfachjs cinerea. 2. ( x 500) 3-porate grain, note protruding pore membrane; 3. (x 500) note faint Y- shaped furrow formed by 3 colpoid streaks united at the poles, and 3 pores, 2 bcing ora; 4. (x 500) 3-colporate grain; 5. ( x 625) 3-syncolporate grain, note granulate colpus membrane; 6. (x500) 4-porate grain; 7. (x500) note distinct verrucae. 8. J'arkia clappertoniana (x 500) polyad Grnria'l3 Pentaclethra niacroplijlla ( x 500). 11. Tetrapleirra trlraptero (x 625). 12. Bosqrtiea nngolensis ( x 1 250) note seieral pores Atoringo oleifera ( x 625). 13. Note 0s. IS-16. Pjcnanrliiis angolensis ( x I 250) Sjzjgirrtti girineense ( x 1 250) syncolporate grains; syncolporate grain. 20. Pandanits randelabrirtti ( x I 250) Adenodoliclios panirirlatiis (x 625). 21. Note opercula. 23. Dalhrgia rcasraplijl- /mi (x 1 250) aberrant, 2-syncolporate grain.

25 Pollen of Nigeriatt plants. I I69 Gram 13

26 170 A{. A. Sowrirtnri metrical; 3-porate, 3-colporate, very rarely 4-porate; oblate, shape in equatorial view variable (P?, E ca pm). Subtectate. NPC: 344, 345 (444). Apertural status variable: many grains have 3 pores (5.6 x3.1 pm) with annuli (1.1 pm wide), membranes grandate, projecting beyond the surface of the grain in polar view, in some of these grains, a Y-shaped furrow formed by three colpoid streaks united at the pole (syncolpoid), can be seen, but the pores apparently bear no relation to the colpoid streaks; in some 3-porate syncolpoidate grains 1 or 2 of the pores are eccentrically situated sub-equatorially in the colpoid streaks and are therefore equivalent to om, while the remaining 2 or 1, respectively, arc pores which have no apparent connection with the colpoid streaks; some other grains arc 3-colporate, the colpi being free at the poles (apocolpium diameter ca. 7.1 k0.7 pm); in yet a fourth category the grains are 3-colporate, with the colpi united at the poles. The colpus membranes in all four types are granulate. Exine 3.0 pm thick (including processes) markedly undulating, smooth, permeated by deeply-incised channels, the resulting sexine islands may lack any definite shape, giving rise to a rugulate pattern, with some of the channels anastomosing, but in general they are verrucose; verruc9e (height 2.1 k0.8 /mi, basal diameter 4.7 f 1.7 Itm) densely spaced, sometimes united basally. Sexine stratification somewhat indistinct. Bacula faintly visible below and between verrucae, (height 0.3 /mi), foot layer 0.6 /cm thick. The separate occurrence of pores and colpoid streaks in several grains is here considered probably to represent a transitional stage in the evolution of 3-colporate grains from 3-porate ones, or vice versa. The author has not found any references to this phenomenon in the available literature. The nearest arc the descriptions of Erdtman (1952, 1966) porate [-colpoidorate (syncolpoidate)], and Sorsa (1969)... 3-porate or-colpoidorate, but without further elaboration. Van Zinderen Bakker et al. (1959) described the grains as being triporate, while Guinet (1969) referred to them as 3-porate and 3-colporate. In the material studied, only monads were found. This agrees with Erdtman s (1952, 1966) observations and to some extent with Sorsa s (1969), grains usually as monads, occasionally clustered in polyads of 4 to 16 grains. Van Zinderen Bakkcr et al. (1959) found only polyads containing 16 grains, while Guinet (1969) found varying numbers - 8, 12, 16, or 16+. The Grarta 13 likeliest explanation of this disparity is probably that individual grains separate easily after acetolysis treatment (van Zinderen Bakker et al., ibid), and illustrates some of thc misleading effects chemical treatments may have on pollen morphology. Parkiu clappertorriaria Keay (PI. 6, Fig. 8). Fresh material. Ibadan Sowunmi 3. Pollen grains clustered in polyads with 20 grains in each, arranged irregularly and asymmetrically; apparently atreme; the polyad oval or rounded in shape, individual grains 3, 4 or 5-sided, distal faces convex, concave or flat on the distal face, proximal faces.wedge-shaped (polyad k3.6 x 84.7 t5.4 /cm). Apertures were indiscernible in this species. Exine 2.4 ycm thick on the distal face. Sexine negatively reticuloid, verrucose in parts. Sexine islands supported by one or more distinct rows of bacula, thin sexinous strands form connecting bridges to the islands in some places. Tectal part 0.8 f0.2 pm, infratectal baculate zone /tm, foot layer 0.6 ko.1 pm, and endcxine /tm thick. The number of grains in a polyad are not easily ascertainable in this species. This probably explains the great divergences in the reports given by earlier workers: van Zindcrcn Bakker et al. (1959) gave the number as 36-40, Guinet (1969) as 1620, and Sorsa (1969) as 16. Only Guinet (ibid.) mentioned the occurrence of 3-4 pores, with costae, in each grain. Peiztac1ethru ntacropliylla Benth. (PI. 6, Figs. 9-10). Fresh material. Ibadan Sowunmi et al. 42. poroidorate; goniotreme, sides convex-oblate (P 35.9, E 50.5 pm). Sexine subtectate. NPC: 346. Pores not distinctly demarcated in equatorial view, in polar view they seem to be elongated laterally. Ora very distinct (diameter ca. 9.8 pm), annuli coarsely granulate (ca. 2.8 pm wide.). Exinc 1.5 pm thick, much thicker at the apertures (3.0 pn), where it pouts. Sexine minutely reticulate. Tectal zone 0.3 pm, the densely but finely baculate zone 0.8 /tm, foot layer 0.4 /cm (1.9 Icm at the apert u rcs). Erdtman (1952, 1966) described the grains as.., van being.. 3-colporate.. brevicolpate Campo et al. (1960) as... 3-colporate, ectoaperture variable and ill-defined, endoaperture circular with an annulus..., Guinet (1969) as 3-colporatc and Sorsa (1969) as 3-colpate, 3-poroidate, or 3-col-

27 porate". These disparities are largely due to the fact that the outer aperture is very. indistinct and could be eithcr a pore or a very short colpus. It is difficult to reconcile Sorsa's (1969) observation of 3- colpate, verrucose grains with those of the present author or of the other authors cited above., Tetrapleura tctraptera (Schum. & Thonn.) Taub. (PI. 6, Fig. 11). Fresh material. Ibadan Sowunmi et al. 19. Pollen grains clustered in polyads with 16, 18, or 24 grains (generally 24) arranged irregularly and asymmetrically; individual grains 3-porate (very rarely 4-poratc); the polyad oval or circular in shape, individual grains isopolar to subisopolar, variable in shape: triangular with straight or convex sides, or tetragonal with one side shorter than the others, or pentagonal (polyad 56.7 k1.4 ~41.6 k2.3,mn, individual grains 17.3 f 1.3 pm). Sexine apparently pcrtectatc. NPC: 344 (444). Apertures consist of distinct, circular pores (diameter 3.2 k0.6 pm), with granulate membranes which protrude beyond the surface of the grain. Exine 1.5 Itm thick, (ca. 2.1 pm thick at the pores). Sexine seems to be very faintly LO-patterned, stratification indistinct. Tcctum 0.5 fo.l pm, baculate zone 0.2 pm (bacula indiscernible), and foot layer 0.8 io.l pm thick. The observations given hcrc agree, essentially, with those given by Guinet (1969) and Sorsa (1969), except that no 6-porate grains or polyads made up of 32 grains were found as indicated by the latter author. Aforaceae Atitiuris africatia Engl. Herbarium material. lbadan Onyeachusim & Binuyo, FHI. porate; goniotreme (sidcs convex) to slightly peritrcme-suboblate (P a k0.7 pm, E 16.8 f0.4 pm). Sexine pcrtectate? NPC: 344. Pores (2.0 t0.3 x 1.9 f0.2 pm), apparently with coarsely granulate membranes. Apoporium diameter ca f 1.3 pm. Exine ca. 0.8 /tm thick. Sexine faintly LO-patterned, stratification obscure. Bosqiriea angoleiisis Ficalho. (PI. 6, Fig. 12). Fresh material. Ibadan Sowunmi et al. 27. Pollen grains isopolar, radially symmetrical; poly- Polleti of Nigerian platits porate (pores 13-15)-pantoporate; suboblate (P 19.8 f1.2 I'm, E pm). Sexine subtectate? NPC: 764. Pores circular (diameter. 1.6 k0.2 pm), margins thin but clearly defined. Exine 1.2,urn thick. Sexinc finely OL-patterned, stratification obscure. Trecirlia africatia Dccnc. Herbarium material. Benin Anozie, FHI. POrate; goniotremc (sides convcx) or peritremcsuboblate (P ca f0.4 pm, E ca ko.l pm). Sexine pcrtectate? NPC: 344. Pores circular (1.7 f0.2 x 1.8 fo.l pm), margins granulate. Exinc ca. 0.5 /tm thick. Scxine faintly LO-patterned, stratification obscure. A foritigacene Moritiga olegem Lam. (P. 6, Figs ). Fresh material. Ibadan Sowunmi et a!. 47, 103. PoIIcn grains isopolar, radially.'symmetrical; 3- colporate; goniot rcme, sides 'convex-prolate spheroidal (P 40.1 k2.5 rim, E 32.8 f2.2 'pm). Sexine sub: tectatc. NPC: 345. Colpi narrow (width 0.9+0:1 pm), united at the poles, margins conspicuously thickened (214 k0.2 pm thick mcdially, thinning toivards the ends);' Ora markedly elongated longitudinally (Icnith 11.9 '+ 0.7 pm, width 3.8 k0.6 pm). Exirie 1.4 pm thick (2.3 /tm thick at the apertures). Sexine very finely and faintly OLipatterned; Tectal part 0.4f0.1 /t.m, baculate zone 0.3 fo.l /Im, and foot layer 0.7 fo.l pm thick. A fjristicaceae Pyctiatitliiis atigolcnsis (Welw.) Warb. (PI. 6, Figs ). Herbarium material. Ijcbu Akinduro, FHI. Pollen grains hetcropolar, bilaterally symmetrical; l-colpatc; amb +elliptical-boat-shaped or kidncyshaped in equatorial view (P 13.8, El 19.2, E, 16.4 pm). Sexine intectate? NPC: 133. Colpi only faintly delimited, practically as long as El* Exine ca. 1.6 Itm thick; Sexine spinulose. Spinules (1.1 pm high, basal diameter 0.5 pm) sharply pointed, density 10 per 50 pm*. Foot layer 0.5 pm, and endexine ca. I.l.pm thick. Gram I3

28 f 72 hf. A. Sowiiiiiiii Ilfyrtaceae Syzygiiiiir giiiirceiise (Willd.) DC. var. giiiirceiisc (PI. 6, Figs ). Herbarium material. Bauchi Jackson, F11I. Pollen grains isopolar, radially symmctrical; 3- colporate (rarely 4-colporate, viz. 3.8% of 830 grains examined); goniotreme, sides straight or convexoblate (P 9.2 /ern, E 16.9 pm). NPC: 345 (445). Colpi united at the poles, faintly demarcated, width ca. 0.7 /em, margins 0.7 pm wide. Ora faint, apparently elongated laterally. Exine 0.6 /m thick (1.1 pm at the apertures). Scxinc.pattern and stratification not discernible. Ocliiiaceae Loplrira laiiccolutu Von Tiegh. ex Kcay. Herbarium matcrial. Ilorin. Ejofor et al., FHI. colporate; peritreme-oblate spheroidal (P 13.5 k 0.9!em, E 13.8 f0.6 pm). Sexine pertectate? NPC: 345. Colpi very faintly delimited (length ca k0.4 pm, width ca. 1.7 to.1 pm). Ora comparatively large, elongated transversely or circular (Icngth 2.7 k0.4 pm, width 3.3 k0.6 pm). Apocolpium diameter 3.9 k0.5 pm. Exinc 0.7 pi thick, pouting at the apertures, apparently smooth, stratification very indistinct. Scxine pattern very indistinct. Oiiratea flora (Schum. & Thonn.) Hutch. & Dalz. ex Stapf. Fresh matcrial. Ibadan Sowunmi et al. 7. Pollcn grains isopolar, radially symmetrical; 3- colporate; goniotreme, sides convcx-oblate spheroidal (P 18.0 f0.5 pm, E 19.7 k0.6 pm). Sexine subteclate. NPC: 345. Colpi faintly delimited, short (length ca. 6.0 f 1.2 /m, width ca. 1.7k0.1 pm). Ora large, elongated transversely (length 3.1 k0.3 /em, width ,11m), margins granulate, absent at the lateral extremities. Apocolpium diameter 13.8 f 1.0 pm. Exine 1.4 pm thick (ca. 2.2 pni at the apertures). Sexine minutely reticulate to apparently striatoreticulate. Lirae 0.4 to.1 pm wide. Striae 0.4 t0.1 pm wide. Tectal part of lirac 0.4 to.l pm, baculatc zonc 0.3 ko.l pm, and foot layer 0.7 ko.1 pm thick (ca. 1.5 f0.2 Icm thick at the apertures). Pallllne Borassirs aetliiopiiiiii Mart. Herbarium material. Calcutta. Wallich s.n. PLS: (Palynological Laboratory, Stockholm, Sweden). Gram I3 Pollen grains heteropolar, bilaterally symmetrical; 1-colpate; amb more or less elliptical-boat-shapcd or kidney-shaped in equatorial view (P 33.6 k2.0/1m, El 63.7k3.0 Itm, E2 44.6k3.8 /em). Sexine sub tectate. NPC: 133. Colpus long (length practically thc same as El), width ca. 5.0f1.2 pm at and near the distal pole, tapering off towards the ends. Exine 1.8 pm thick. Scxine verrucose, finely and minutely reticulate (OL-pattern). Muri simplibaculate. Lumina polygonal. Tectal part of muri ( pm thick), provided with verrucac (height 1.8 k0.2 pm, basal diameter 2.7 t0.3 pm), density 5 per 10 pm*, infratectal baculate zone 0.4 ko.l /mi thick, and foot layer 1.0 f0.2 pm thick. Elaeis giiiiimrsis Jacq. var. dura. Fresh material. Eknin: NIFOR, Mcncndcz et al. Pollen grains heteropolar, radially symmetrical or bilateral; l-colpate [3-chotomocolpatc (81 y, of grains examined), less often 4-chotomocolpate]; amb more or less elliptical-boat-shaped or kidney-shaped in equatorial view (P 16 pm, El 41 pm). 4-chotomocolpate grains: rounded-triangular, sides, concavcboat-shaped in equatorial view (P 17.5 /em, E 43 pm). Sexine subtectate. NPC: 132 (133). Colpi arms 18,tun long, 2.1 pm wide, usually reaching the equator, margins wavy. Exine 1.4 /em thick. Sexine pattern variable: vermiculate to minutely subreticulate to negatively subreticulate, channels with sexinous strands (clearly visible at low focusing of objective). Tectal zonc 0.8 Icm, baculate zone 0.2 /em, and foot layer 0.4 Inn thick. Bronckers (1967) did not record thc presence of 3- and 4-chotomocolpate grains. Hjphaeiie tliebaica (Linn.) Mart. Herbarium material. Zaire Wagemans 610, Herb. Brussels. Pollcn grains heteropolar, bilaterally symmetrical; 1-colpate; amb more or less elliptical-boat-shaped or kidney-shaped equatorial view (P 31.0 k 1.9 pm, E, 42.0 k2.3 /em, E k1.8 pm). Scxinc subtectate. NPC: 133. Colpus long (length practically the same as El), width ca. 5.8 Itm at and near the distal pole, narrowing towards the ends. Exine 1.3 pm thick. Sexine verrucose, finely and minutely reticulate (OL-pattern). Tectal part of muri (0.4 to.1 /em thick), provided with vcrrucae (height 1.2t0.0 Icm high, basal diameter 1.4tO.O {em), density 12 per 10 pm*, infratectal baculate zone

29 0.4 fo.0 pm thick, and foot layer pm thick. Both B. aetliiopiirin and H. tliebaicn have similar pollen grains, those of the latter being somewhat smaller. p/roeiiix recliitatn Jacq. Herbarium material. Natal. Stellcnbosch 4271, PLS. Pollen grains heteropolar, bilateral; I-colpatc; elliptical in polar view-boat-shaped or kidney-shaped in equatorial view (P 17.0 f1.8 pm, El 26.0 ko.1 pm, Ex 20.5 & 1.9 pn). Sexine subtectate. NPC: 133. Colpus long (length practically the same as Ed, width 3.1 f0.6 pm at and near the distal pole, tapering towards the end. Exine 0.9 pm thick. Sexine minutely reticulate. Muri (0.3 fo.0 pm widc), simplibaculate, bacula not always distinctly visible. Lumina 0.5 f0.2 /cm wide. Tectal part 0.3 pm, baculate zone 0.3 pm, and foot layer 0.3 Itm thick. Pairdaiiaceae Priiirlnirrrs caimdelubririii Beauv. (PI. 6, Fig. 20). Herbarium material. Mai Idoamu Latilo & Daramola, FHI. Pollen grains heteropolar, bilateral; 1-poratc; amb more or less clliptical or spherical-oval or more or less elliptical, rarely kidney-shaped, in equatorial view (P 17.6 pm, E 19.8 ym). Sexine apparently intcctatc. NPC: 134. Pore nearly isodiamctric (3.5 x 3.9 pm). Exine 1.2 Itm thick (including processes). Sexine spinulose; spinulcs 0.9 /tm high, basal diametcr 0.4 Irm, density 22 per 12 pm*. Foot layer 0.3 pm thick. Pnpilioiinceoc Adeiiodoliclros pniricirlntrrs Hutch & Dalz. (PI. 6, Figs ). Herbarium material. Zaria Latilo, FHI. Pollen grains isopolar, radially symmetrical; 3x01- porate; goniotreme, sides convex to straight-oblate spheroidal (P 36.2 & 1.4 pm, E 40.0 f2.6 pm). Sexine subtcctatc. NPC: 345. Colpi pm long, 3.9 f0.3 pm wide medially, sometimes tapering away at thc ends,.margins distinct (ca. 4.7 k0.7 pm thick). Ora transversely elongated or nearly isodiametric (length 8.2 k0.7 pm, width 9.0 k 1.2 pm), provided with coarsely granulate opercula which usually project beyond the general surface of thc grain. Apocolpiurn diameter 18.2 f 1.7 pm. Exine ca. 0.9 pm thick. Sexine reticulate, rcticulation finer and fainter in the apocolpia than in the mesocolpia. Muri 0.5 to.l,mn wide, simplibaculate. Lumina Itm widc. Tcctal. part of muri ca. 0.3 Ifr0.l pm, baculate zone ca. 0.4 to.1 pm, and foot layer ca. 0.4 ko.l pm thick. Bupliin iiitida Lodd. Fresh material. lbadan Sowunmi et al! 35. colporate, occasionally 4-colporate; peritreme-sub-.prolate (P 27.5 f 1.7 pm, E 22.6 f 1.7 pm). Sexine subtectatc. NPC: 345 (445). Colpi 23.0 f1.0 Itm long, 2.8 ko.1 /tm wide, sometimes sharply constricted medially, margins distinct. Ora elongated longitudinally (length 8.1 ko.1 pm, width 2.8 fo.l pm). Apocolpium diameter 7.3 k0.2 pm. Exine 1.5 Itm thick. Sexine finely rcticulatc. Muri 0.2 ko.1 Itm widc. Lumina 0.7 k0.2 Itm wide. Tectal part of muri /tm, baculate zone pm, and foot layer 1.OkO.l,mi thick. Dalbergia ecastnpliylliriti (Linn.) Taub. (PI. 6, Fig. 23; PI. 7, Figs. 1-3). Herbarium material. Lagos Okafor & Macaulay, FHI. Pollen grains heteropolar, radially symmetrical; 3-colporate; peritreme to goniotreme, sides convexsubprolatc (P 28.8 pm, E 22.7 pm). Sexine subtectate. NPC: 345. Colpi united at one pole but free at the other, width 0.9 pn, may be narrower or wider medially where they traverse thc ora, margins conspicuous (2.0 pm thick), narrower but apparently deeper medially (1.2 prn thick), not distinct at the ends of colpi. Ora conspicuous, clongatcd longitudinally (length 6.8 /tm, width 5.1 pm). Apocolpium diameter 3.5 pm. A few aberrant grains occurred: 2-colporate, the colpi united at both poles; in one grain there seemed to be faint indications of a third 0s; in another there was a pointed bulge occupying the site of the third colpus. Exine 2.5 pm thick. Sexine minutely reticulate. Muri homobrochate. Tectum 0.4 Itm thick, the dcnscly baculate zone 0.7 pm, the foot laycr.l.1 pm, undulating, especially on the distal surface, and the endexine 0.3 pm thick. Thc aberrant grains referred to occurred very rarely and may be duc to malformation. Erythriirn addisoitine Hutch. & Dalz. Herbarium material. lbadan Onachie, FIII. Grnna 13

30 174 M. A. Soivirrirrri porate; goniotrcme, sides convex-oblate spheroidal (P 37.2 Itm, E 39.4 pm). Sexinc subtcctate. NPC: 344. Pores elongated longitudinally (length 9.4 rim, width 8.0 pm), membranes thin but conspicuous, protruding beyond surface of grain, annuli distinct (a. 2.1 Itm wide). Apoporium diameter 27.4 pm. Exine ca. 2.4 pm thick. Sexine reticulate, curvimurate. Muri (1.3 pm widc) discontinuous in some places, duplibaculate (somctimcs simplibaculatc), baculcs only faintly visiblc. Lumina (2.5 pn wide) mostly narrow and elongated, sometimes polygonal. Tectal part of muri ca. 0.8 Itm, baculate zone 0.3 pm, foot layer 0.3 pm,.nexine, 0:3 pm, and nexinez 0.7 pm thick. Electromicrographs are needed to confirm the exinc stratification indicated above. E. rtiildbraedii Harms (PI..7, Fig. 4). Fresh material. Ibadan Sowunmi et al. 15. porate, rarely 4-porate; goniotreme, sides straight to convex-suboblate (P 28.3 & 1.2 Itm, E 32.2 f 1.1 pm). '.. Sexine subtectate.' NPC: 344 (444). Pores elongated longitudinally (6.4 f0.4 x 5.6 k0.5 pm), with coarsely granulate opcrcula which project beyond the general surface of the grain. Apoporium diameter 24:3 +1:9 I'm: Exine 1.5 pm' thick. Sexine coarsely but rather faintly reticulate especially at low focus, reticulation finer towards'and around the pores, curvimurate in. places. Muri (0.8 ko.1 /tm wide) discontinuous in places, simpli- to duplibaculatc, bacula only faintly visible. Lumina (1.7 k0.7 pm wide), with a few dark dots (bhcula?) within some of them. Tectal part of muri 0.3iO.l,hn thick, (slightly thicker'at thepoies), apparently with small verruca-like processes, infratectal baculate zone Itm thick, and foot layer 0.9 ko.1 pm thick. Electronmicrographs are needed to ascertain. whether 'supratectal verruca-like processes are prcsent or not. Lotichocorpirs sericeirs (Poir.) H.B. & K. (PI. 7, Figs. 5-6). Fresh material. Ibadan Sowunmi et al. 43. Pollen grains isopolar, radially symmetrical; porate; goniotreme, sides straight to convex-oblate spheroidal (P 27.4 f 1.2 /tm, E 28.3 k0.7 pm). Sexine subtcctate. NPC: 345. Colpi 19.9 t. 1.3 pm long, width 3.3 k0.4 Itm wide medially, gradually becoming slightly narrower or Gratin 13 tapering off towards the ends. Ora comparatively large, elongated transversely, (length 6.4 k0.4 /tm, width 11.2 k0.7 pm, sometimes with a medial constriction (4.5 k0.8 /im wide). Very occasionally some unusual grains occurred, possessing what seemed to bc a pseudocolpus extending between two true colpi and at right angles to them (PI. 7, Fig. 5). Apocolpium diameter 9.7 f0.9 pm. Exine 1.8 pm thick (ca. 1.1 pm thick towards the apertures). Sexinc finely reticulate. Muri 0.4 k0.1 pn, wide. Lumina 0.7 ko.1 /rm wide. Tectal part of muri 0.5 ko.1 pm, baculatc zone 0.3 ko.1 pm, and foot layer 1.OkO.1 pm thick. Mileffia fkoririirigii (Schum. & Thonn.) Bak. Herbarium material. Kabba Jackson, FHI. Pollen grains isopolar, radially symmetrical, 3-colporate, very rarely 4-colporate (in 0.4% of the grains examined); goniotrcmc, sides convex, to peritrcme-subprolate (P 27.2 pm, E 21.2 pm). Scxine subtectate. NPC: 345 (445). Colpi 21.7 pm long, 2.1 Itm wide, sharply constricted medially: in some grains colpi widest medially, narrowing towards the ends, margins narrow but distinct (0.8 /tm widc). Ora indistinctly demarcated, apparently elongated laterally, with coarse membranes. Apocolpium diameter 9.3 pm. Exine 1.1 pm thick, thinning sharply towards the apertures. Sexine finely reticulate. Muri 0.4 prn wide, simplibaculate. Lumina 0.5 Itm wide. Tectal part of muri 0.3 pm, baculatc zone 0.2 pm, foot layer 0.4 pm, and endexine 0.2 Itm thick. Pferocarpirs eritraceirs Poir. Herbarium material. Oyo Stanfield, FHI. Pollen grains isopolar, radially symmctrical; 3-colporate; goniotreme (sides convex) or pcritrcmc-prolate spheroidal (P 19.5 k0.8 pm, E 17.6 k0.5 Itm). Sexine subtectatc. NPC: 345. Colpi ca k 1.0 pm long, ca. 1.2 ko.2 pm wide. Ora comparatively large, elongated transversely or almost isodiamelric (length /tm, width 6.5 k0.7 rim), operculatc. Exine 1.3 pn thick, slightly thinner towards the apertures. Sexine finely and minutely reticulate. Tectal part of muri 0.4k0.1 pm, baculate zone 0.4 ko.1 pm, and foot layer 0.5 ko.1 /tm thick. Proteaceae Profea elliotfii C. H. Wright var. elliottii (PI. 7, Figs. 7-12). Herbarium material. Niger: Gwaha Kurmi Jia, FHI.

31 Pollen of Nigerian plants. I 175 Plate 7. Figs Dnlbergin ecastnpli~llrrnl (contd.) (x 1 250) syncolporate grains; 3. aberrant, 2-syncolporate grain. 4. ErytArina mildbroedii (x 1 250) note protruding opercula Lonchocarpus sericects x I Aberrant grain Protcn clliottii var. rlliottii (x I 250) 7. equatorial view, 3-porate grain; 8. Type 11; 9. Type I; 10. Type 111 (transitional grain); 11. Type IV (4-porate grain); 12. (x 1 000) noie faint Y-shaped furrow terminating at the pores. Gram 13

32 176 hf. A; Sowiititiii Downloaded by [ ] at 23:10 21 November 2017 Pollen grains polymorphic, comprising four distinct types. Type I [46% of the 250 grains examined), described in detail- subsequently. Type I1 (45.3%); isopolar, radially symmetrial; 3-poratc; goniotreme, sides convex (E 30 pm). Type I11 (1.4%): transitional grains, 'sub-isopolar, asymmetrical; 3-porate, with a slight protrusion' of thickened exine in place of a fourth pore; goniotreme (four-sided (sides of unequal length) sides concave). Type IV (7.3%): subisopolar, radially symmetrical; 4-porate; goniotrcme (foursided, one side slightly shorter than the rest, sides straight or concave). Type I: isopolar; radially symmetrical; 3-porate; goniotreme; sides straight or concave-oblate (P ca f 1.4 pm, E 29.9 &.I5 pm). Sexine subtectatc. NPC: 344. Pores large (length :ca. 4.8k0.4 pm, width a pm), membranes granulate; in a polar view of a few grains a central, faintly delimited threearmed furrow-like streak terminating at the pores, was observed (see PI. 7,.Fig. 12). Apoporium diameter 26.1 f 1.6 pm. Exine ca. 1.3 /tm thick. thinning towards the apertures. Sexine negatively reticuloid, with channels traversed by thin sexinous strands. Tcctal part ca pm, baculate zone ca. 0.3 fo.1,mi, and foot layer ca; 0.7 to.0 pm thick; The occurrence'of some grains with 'a three-armed furrow terminating at the pores is noteworthy. This probably represents a transitional stage in the formation of 3-porate grains. As far as is known, this is the first record of such occurrence in this species. It is perhaps analogous to the situation in the immature 3-porate grains of 'Scierosbernra iirnririii. (Palmael described by Erdtman & Singh (1957). The heterogeneity encountered here suggests that this species is probably a hybrid. If so, this is yet another example of hybridism occurring within the Proteaceae, a rare phenomenon' in 'this family (Erdtman 1952, 1966). Another example is a Bnrrksia species, B. rtieriziesii whose pollen grains arc "2-5 aperturate... apertures +circular" (Erdtman, ibid.) Rlrizopliorrr Irarrisonii Lccchman (PI. 8, Figs. 1-2). Herbarium material. Niger delta Marsh, FHI. colporatc; peritreme to slightly goniotreme, side convcx or straight-prolate sphcroidal (P 20.1 'pm, E 19.7 pm). Sexine subtectate. NPC: 345. Colpi ca Irm long, 1.4 /tm wide medially, tapering off towards the ends. Ora large, markedly elongated transversely (length 2.5 pm, width 8.2 pm), lateral extremities indistinctly demarcated. Apocolpium diametcr ca 6.5 pm. Exine ca. 1.1 /cm thick (2.3 pm at the apertures). Sexine finely reticulate. Muri 0.3 /tm wide. Luniina 0.7 pm wide. Tectal part of muri ca. 0.3 pm, baculate zone ca. 0.3 pm, foot layer ca. 0.5 pm (ca. 1.7 pm at the apertures). R. niatigle Linn. (PI. 8, Fig. 3). Herbarium material. Lagos Jackson, FHI. Pollen grains isopolar, radially symmetrical; 3x01- porate; pcritreme-prolate spheroidal (P ca pm, E Ca pn). Scxine subtectate. NPC: 345. Colpi ca Jim, ca. 1.3 pm wide, slightly constricted medially. Ora large, markedly elongated laterally (length ca. 1.4 pm, width ca. 8.8 am), slightly wider towards the extremities which are not clearly delimited. Apocolpium diameter 6.7 /mi. Exinc 1.6 pm thick. Scxine minutely reticulate. Muri 0.3 /tm. wide. Lumina 0.7 Itm wide. Tectal part of muri 0.5 pm, baculate zone 0.5 pm, foot layer 0.6 Itm thick. Erdtman (1952, 1966) observed 4-colporatc grains in the Rhizophora spccies which he studied, Assemien's (1969) observations arc in general agreement with the present ones. Rosacene Pnritiari criratelli/olia Planch. ex Benth. Herbarium material. &ria Darter, FHI. colporatc; goniotreme, sides convex or straight-probably prolate spheroidal? (P ca pm?, E 29.1 f2.2 pn). Sexine subtectate. NPC: 345. Colpi dimensions difficult to ascertain, margins conspicuously thickened (2.3 k0.3 /tm wide). Ora apparently transverscly elongated (dimensions difficult to ascertain). Apocolpium diameter 6.7 f 1.0 pm. Exine 2.8 pm thick, thinner at the apertures (ca. 1.4 pm), markedly undulating. Sexine finely OL-patterned. Tectal part 0.6 k0.2 pm, densely baculate zone 0.6 f0.2 pm, and foot layer 1.6 k0.4 pm thick. P. kerstiiigii Engl. Herbarium material. Nsukka Consens, Ffil. COIporate; goniotrcme, sides straight or slightly concave-oblate (P 31.8 pm, E 44.4 pm). Sexine subtcctale. NPC: 345. Colpi ca pm? long, ca. 1.6 pm wide medially

33 Pollen of Nigerian platits. I 117 Plafc 8. Figs Rliizopliorn lmrrisonii (x 1 250). 3. R. tirangle (x 1 250) Canrliirrnt subcordalum 6-8. Garrrriera panicrrlata 6-7. (x I OOO) aberrant, 2-colporate grains; 8. (x 1 250) 3-colporate grain Aforclin scncgalcnsis pore. (x 1 250). 9. Note pore and 0s; pororate grain h'aiiclea didcrrichii (x 1 250) colporatc grains; colporate grain. I5. Claitserm ariisara ( x 1 250). 16. Blighifl sapid0 (x 1 250). 17. Paiillinia pinnola (x 1 250) note larsc Gratin I3

34 tapering off towards the ends, margins granulate, very conspicuously thickened (3.8 /em wide, tapering off towards the ends), in polar view the margins arc horse-shoe shaped. Ora.very large, markedly elongated laterally (length ca pm, width ca /em, slightly constricted medially) membranes coarsely granulate. Apocolpium diameter 8.4 pm. Exine 2.8 /em thick, much thinner at the apertures (0.7 pi). Sexine stratification indistinct, pattern seems to be vermiculoid. Kiibinceac Cnritliiiiiri siibcordutiirii DC. (PI. 8, Figs. 4-5). I Ierbariuni material. Benin Adeoye.BC 24/472, FHI. porate; pcritremc to goniotreme, sides convex or straight-oblate spheroidal (P 36 /em, E 37.4 /em). Scxine subtectate. NPC: 344. Pores nearly isodiametric (5.9 /em x 5.2/cm), annuli granulate (1.7 /im wide). Apoporium diameter 24.5 pm. Exinc 2.9,mi thick. Scxine coarsely reticulate. Muri 0.6 pm widc, distinctly simplibaculate. Lumina 2.2 /em wide, with, occasionally, one to three bacula. Tectal part of niuri 0.5 pm, ramibaculatc in parts, baculate zone- 1.9 /ern, lpcula comparatively stout (diameter 1.0 pm), foot layer 0.5 pm thick. Bonckers (1967) described the pollen grains of this species as 3-colporate ectoaperture is short, but no indication of the Occurrence of colpi was found during the present investigation. Gnertriern pniiiciilntn Bcnth. (PI. 8, Figs. 6-8). Herbarium material. Zaria Jackson 162, FHI. Pollen grains isopolar, radially symmetrical; 3-(2-) colporate (I 1.3% of 160 grains examined were 2-colporate); pleurotrenie (rounded triangular)- oblate spheroidal (P 35.0 /em, E 37.4 pm). Sexine subtectate. NPC: 345 (245). Colpi short and narrow (length ca. 18.9,mi, width ca. 2.0 pm) margins very coarse and conspicuous (ca. 5.4 /tm wide). Ora large, transversely elongated (length ca. 4.5 pm, width ca /em), lateral ends indistinctly demarcated. Apocolpium diameter 21.4 Itm. Exinc 1.6 pm thick, considerably thicker at apertures (4.7 pm; the extra thickness apparently due to an additional layer situated below the foot layer, not very obvious seen in the interapertural areas), gcntly undulating. Sexine coarsely reticulate, curvi- Grana I3 murate in most parts. Muri 0.6 /em wide, distinctly simpli- to duplibaculate. Luniina 0.9 /em wide. Tectal part of muri 0.6 [em, baculatc zone 0.4 /em, foot layer 0.6 /em thick. An unusual aberrant grain was seen (Plate 8, fig. 6) transitional between 2- and 3-colporate grains; it has 2 compound apertures, but was rounded-triangular in shape likc a 3-colporate grain. It is not clear why a third aperture failed to develop. An ontogenctic study may provide the clue. Afi/rngy/in iircriiiis (Wild.) 0. Kuntzc. Herbarium material. Abuja-Keffi Road Olorunfemi, FHI. colporate; goniotreme (sides convex)-oblatc spheroidal (P /em, E 15.6 k0.5 /em). Sexine subtectate. NPC: 345. Colpi only faintly delimited. Ora longitudinally elongated (length pm, width 1.3 k0.3 prn), margins distinct (0.8 t0.2 /em wide). Apocolpium diameter 3.5 t0.4 pm. Exine 1.1 /em thick, tapering towards the apertures. Sexinc reticulate. Muri 0.4 t0.1 /em wide, distinctly sirnplibaculate. Lumina jem wide. Tectal part of muri 0.3 fo.0 pm, baculate tone 0.4 ko.1 /em, and foot layer /em thick. Morelin saiekwleitsis A. Rich. ex DC. (Plate 8, Figs ). Herbarium material. Zaria Jackson 205, FHI. Pollen grains isopolar, radially symmetrical; 344)- por(or)ate (3% of 500 grains examincd were 4-por- (or)ate), very rarely 2-por(or)ate; goniotrcme, sides convex or straight-suboblate (P 19.4 Itm, E 22.7 /em). Sexinc subtectate. NPC: 344, 346 (444, 446, 244, 246). Most grains with pores; longitudinally elongated or nearly isodiametric (length 4.1 pm, width 2.9 pm), annuli very distinct (2.6 pm wide); some grains with transversely elongated ora (length ca. 3.2 pm, width ca. 8.9 pm), faintly delimited. Apoporium diameter 13.7 pm. Exine 1.3 /em thick, thicker at the apertures (2.6 pm). Sexine reticulate. Muri 0.5 pm wide, distinctly simplibaculatc. Lumina 0.9 Itm wide. Tectal part of muri 0.4 pm. baculate zone 0.4 /em, foot layer 0.5 /em (2.0 /cm at apertures). Nuirclea didcrrichii (De Willd. & Th. Dur.) Merrill (PI. 8, Figs ). Herbarium material. Ijebu Adebusuyi et al., FIII.

35 colponte (very rarely 2-colporate (PI. 8, Fig. 14); peritreme-prolate spheroidal (P /em, E 15.0 k0.6 /mi). Sexine subtectate. NPC: 345 (245). Colpi ca t 1.8 /em long, width ca /em at and near the middle, tapering off at the ends. Ora longitudinally elongated (length /em, width 1.8 k0.2 pm), margins distinct (0.7 ko.1 /em wide). Apocolpium diameter 4.3 k0.3 pm. Exine 1.4 /em thick. Scxine reticulate. Muri 0.3 k 0.1 Itm wide, distinctly simplibaculate. Lumina 0.6 ko.1 /tm wide. Tectal part of muri 0.3 ko.1 pm, baculate zone 0.5 ko.1 [em, and foot layer 0.6 ko.1 pm thick. Rirtaceae Clairseria ariimtu (Willd.) Hook. f. ex Benth. (PI. 8, Fig. 15). Herbarium material. Niger Abiai, FHI. colporate; oblate-subprolate (P 23.6 /ern, E 19.1 /em). Sexine subtectate. NPC: 345. Colpi 17.2 /em long, 1.5 /tm wide at and near the middle, slightly narrower towards the ends. Ora transversely elongated (length 1.9 pm, width 6.1 [em), lateral extremities vague. Apocolpium diameter 5.6 Irm. Exinc 1.3 /ern thick. Sexine striato-reticulate.'muri arranged in k parallel ridgcs with perpendicular strands bridging the ridges, 0.3 /em wide, simplibaculate. Lumina 0.8 /em wide. Tectal part of muri 0.4 /em, baculate zone 0.4 Irm, fiot layer 0.5 pn. SaIlIJYfC7CCaC Ilorllalirrnr nlynieri Hutch. & Dalz Herbarium material. Onatia Okafor ct al., FHI. colporate; peritreme-prolate or subprolate (P 14.5 [em E 9.9 /em) or P 14.1 /em, E 11.3 /em, respectively). Sexine subtectate. NPC: 345. Colpi ca Irm long, ca. 1.6 prn wide, margins distinct (ca. 0.7 /em wide). Ora laterally elongated (length ca. 1.8 /em, width ca. 4.0 pm), lateral extremities vague. Apocolpium diameter ca. 2.4 /em. (Dimcnsions derived from subprolate grains.) Exine minutely reticulate. thickness and statification impossible to ascertain. Sapindacene Dliglriu sapidu Konig (PI. 8, Fig. 16) Fresh material. Ibadan Sowunmi et al. 48. Pollen grains izopolar, radially symmetrical; 3- colporate; peritreme or goniotreme, sides straight or convex-prolate spheroidal (P /em, E k 1.1 /em). Sexine subtcctate. NPC: 345. Colpi pni long, width 2.1 k0.3 /em at and near thc ends, sharply constricted in the middle, margins distinct. Ora longitudinally elongated (length 4.0 k0.4 /em, width p ). Apocolpium diameter pm.. Exine 1.3 /em thick. Sexine striate to striatoreticulate. Lirae 0.3 fo.l /em wide, simplibaculate. Striae 0.5 ko.1 pm wide. Tectal part of lirae 0.4 LO.1 pm, baculate zone 0.5 ko.l /em, foot layer 0.4 ko.l /em thick. l?. irriijrgafa Bak. Fresh material. Ibadan Sowunmi et al. 36. colporate; peritreme and goniotreme, sides straight or convex-prolate spheroidal (P 24.4 _+ 1.4 /em, E 21.3 & 1.1 pm). Scxine subtectate. NPC: 345. Colpi ca f 1.4 /ern long, ca. 2.6 k0.4 /em wide, slightly narrower towards the ends. Ora transversely elongated, often poorly defined (length ca. 2.6 k0.5 [em, width ca. 4.5 k0.5 pm). Apocolpium diameter 4.3 k0.6 /em. Exinc ca. 1.4 pm thick. Sexine striate to striatoreticulate. Lirac 0.4 ko.1 /em wide. simplibaculate. Striae 0.4 fo.l /em wide. Tectal part of lirae I'm, baculate zone ca /em, foot layer ca. 0.7f0.1 prn thick. Lccariiodiscrrs criponioides Planch. cx. Bcnth. Fresh material. Ibadan Sowunmi et al. 31. Pollen grains isopolar, medially symmetrical; 3- colporate; goniotreme, sidcs straight or convex. or pcritremc-prolate spheroidal (P 23.6 f 1.3 /em, E 20.9 L 1.4 pin). Sexinc subtectate. NPC: 345. Colpi 18.4 kl.3 /em long, width 0.9f0.3 Itm, slightly constricted in the middle. Ora longitudinally elongated (length 4.8 k0.7 pm, width pm); in some grains a pscudocolpus occurs, extending between two true colpi. Apocolpium diameter 5.2k0.1 pm. Exine 1.4 /em thick. Sexine striate to striato-reticulate. Lirae 0.4 fo.l Irm wide, simplibaculate. Striae 0.4 ko.1 prn wide. Tectal part of lirae 0.5 ko.1 pm, baculate zone 0.2 fo.0 pm, foot layer 0.7 ko.1 /em thick. Paullirria piiiitofn Linn. (PI. 8, Fig. 17). Fresh material. Ibadan Sowunmi et al Pollen grains isopolar to subisopolar, radially Grm 13

36 symmctrical; 3-porate (rarely 4-porate, vit. only 0.5% of the 860 grains examined); goniotrcme, sidcs concave to.straight-oblate (P 27.0 pm, E 47.3 pm). Scxine subtectate. NPC:.344 (444). Pores.slightly elongated laterally, sometimes circular (length.6.4 pm,.width 7.8 pm) mcmbrancs granulate, usually protruding bcyond thc surface of grains; in rarc cases (0.3 :(, of the 860 grains examined) a 34it furrow, stopping just short of the 3 porcs, occurs. This is probably analogous to the situation in some grains of Protea elliottii var. ellioffii (q.v.) Apoporium diameter 35.1 pm. Exine 1.3 Itm thick, tapering towards porcs. Sexinc fincly reticulatc, reticulation niuch finer and rather indistinct near and around porcs. Muri 0.6 /tm wide, simpli- to duplibaculatc. Lumina 0.7 p i wide. Tectal part of muri 0.4 itin, baculate zone 0.3 /mi, foot layer 0.6 pin. The pollen grains of Ofiglria and Lecar~iodircirs are very simifar, and strikingly different from those of Pnirllirria. This finding docs not, on the whole, agree with the gcneric affinities bascd on gross morphology (cf. Keay et al. 1963, Hutchinson RC Dalziel ). Sap0 facerme ilirfryospcrrrrr~rri parorloxwi (Gaerln. I.) Hcpper (PI. 9, Fig. I). Herbarium material. Zaria Lowe 81, FHI. Pollen grains isopolar, radially symmetrical; 4- colporate; pcritrcme-subprolate (P 36.1 k 1.9 I'm, E 29.5 f 1.8 pm). Sexine subtectate. NPC: 445. Colpi 29.0 k 1.0 /rm long. width 1.1 k0.2 pm, margins distinct (2.7k0.5 pm thick at and near the middle, becoming narrower towards the ends). Ora transversely elongated (length 4.4 k0.6 pm, width 7.0 t0.9 pm). Apocolpium diameter ca. 9.7 f0.7 pm. Exine ca. 1.5 /cm thick. Scxine faintly and minutcly reticuloid. Tectal part of niuri ca. 0.5f0.1 pm, baculatc zone ca. 0.3 f 0.1 pm, foot layer 0.7 ko.1 Icm thick. Gucrs et al. (1971) found a few 3- and 5-co1- porate grains. Mdacarrflia alrri/olia (Baker) Pierre. Fresh material. lbadan Sowunnii et al., 33. Pollen grains isopolar, radially symmetrical; 4- colporate; pleurotrcme, (roundcd tetragonal) sides concavc or straight-prolate (P 35.8k1.7 Irm, E 26.2 k 1.2 pm). Sexinc subtectatc. NPC: 445. Colpi 25.5 k I.O/tm long, width 1.4 k0.3 Icm a1 and near the ends with a constriction in the middle. Ora transvcrsely clongated (Icngth 2.1 k0.4 pi, width 4.0 k0.4 pm). Apocolpiuni diameter I.3 pm. Exine 2.3 /mi thick. Sexine pattern rather obscure, but sccms faintly rcticuloid. Tectal part 0.5 k0.l pm, baculatc zone 0.4 ko.1 pm, foot layer 1.4 k0.1 /tm thick. Aiirnirsops mrrreckei Engl. Herbarium material. Onitsha Joncs 2709, FHI. Pollen grains isopolar, radially symmetrical; 4x01- porate; goniotrerne (tctragonal), sides strnight or slightly convex-prolate spheroidal (P 28.0 k 1.5 /mi, E 25.4 f0.9 /mi). Scxine subtectate. NPC: 445. Colpi 19.8 L- 1.3 Icm long, width 0.7 ko.1 pm. Ora transversely clongated (length 2.7 k0.2 /mi, width 6.9 k0.5 pm), apparently operculate, bordered by granulate annuli. Apocolpium diameter 9.1 f 1.0pm. Exine 1.0 /mi thick (ca. 2.7 pm thick at thc apcrtures). Sexine minutely reticulate. Tcctal part of muri 0.3 to.l pm, baculate zonc 0.3 ko.1 pm, foot layer 0.4 +O.O I'm thick. Syrrsepaliori diilcijicim (Schum. & Thonn.) Dsniell. Fresh material. Ibadan Sowunmi et al., 25. Pollcn grains isopolar, radially symmetrical; 4- colporate, rarely 5-colporatc; goniotreme (tctragonal) sidcs straight or slightly convex-subprolate (P 26.7 k 0.9 pm, E 22.8 k0.9 /h). Sexinc subtectate. NPC: 445 (545). Colpi ,tun, width 1.8 k0.2 Itm, margins conspicuous (1.7 k0.3 pm thick in thc middlc, narrowing sharply towards the ends). Ora transversely elongatcd (length 2.6 k0.3 Itm, width 6.8 k0.4 Im). Apocolpium diarncter 6.6 & 1.0 pm. Exine 1.6 pm thick, pouting at thc apertures. Sexinc pattern faint and indistinct but seems to be finely rcticuloid. Tectal part of niuri 0.4k0.1 pm, baculate zonc 0.3 ko.1 /mi, foot layer 0.9 ko.1 pm thick. The pollen grains of all the species studied in this family are, on the whole, similar. Silt mroribaccae Harrrioa klairiearm Pierre & Engl. Herbarium material. Adamawa Latilo & Daramola, FHI. colporate; lobate-prolate (P 27.6kl.l pm, E 16.1 k 1.3 pm). Szxine subtectate. NPC: 345. Colpi a & 1.8 Itm long, width ca itm,

37 Polteri oj Nigerinn plmits. I 18 1 Plate 9. Fig. I, Uutr~ospcrniio~i parndoosrmt ( x I 250). 2. sclerosjloti (x I 250). 6. Note 2 opercula, one each at 2, and bfanso/iia alfissima ( x I 250). 34. h'esogordonia paparerifcrn 6 o'clock. positions. 9. Grewia mollis ( x 625). 10. Cclfisinfegri- (x I 250). 3. Note opercula in sifrr at and 6 o'clock Jolin (x 1 250). positions. 5. Sferrrrlin oblonga (x I 250). 6 4 Triplochifon Grona I3

38 182 hf. A. So~virtittii slightly constricted medially. Ora transversely elongated (length ca. 1.5 ko.1 pm, width ca. 4.5 ko.8 pm, also slightly constricted medially). Exine 1.5 pm thick. Sexine reticulate. Muri 0.6f 0.1 /tm wide, simpli-to duplibaculate. Lumina 0.8 t 0.2 /tm wide. Tectal part of muri 0.4 ko.1 pm, baculate zone 0.5 fo.l pm, foot layer 0.6 ko.1 /tm thick. If. itriditlafa (Guill. & Perr.) Planch. Herbarium material. Benue Keay, FHI. Pollen grains isopolar, radially symmetrical; 3x01- porate; peritrenie-prolate (P 26.5 ko.8 pm, E 17.6 k 1.2 pm). Sexine subtectate. NPC: 345. Colpi 21.9f1.2 pm long, width 1.4f0.3 /em with a medial constriction. Ora transversely elongated (length 1.8 k0.2 pm, width ca. 5.5 f0.6 pm). Apocolpium diameter /em. Exine 1.3 pm thick (ca. 1.5 /tm thick at the apocolpium). Sexine reticulate. Muri pm wide, simpli- to duplibaculate. Lumina 1.0 f0.3 pm wide. Tectal part of muri 0.4 ko.1 pm, baculatc zone 0.5 fo.l pm, foot layer 0.4 ko.1 /em thick. Erdtman (1952, 1966) noted the occurrence of scattered rods or granules in the lumina. The present investigation seems stronger than Erdtman s investigations to support the separation of Irvingiaceae as a distinct family from the Simaroubaceae, a consideration originally based on gross morphological and anatomical features (cf. Hutchinson & Dalziel, ). and not the treatment by Englcr (cited in Erdtman, 1952, 1966, p. 406) in which the Irvingioideae is placed as a tribe within the family Simarou baceae. Sf ercirliaceae Cola acirriibiafa (P. Beauv.) Schott. 8c Endl. Fresh material. Ibadan Sowunmi 49. Pollen grains isopolar. radially symmetrical; 3-colporate; goniotreme, sides convex-suboblite (P 32.1 f 1. 4,urn, E 38.4k1.5 pn). Sexinc subtectate. NPC: 345. Colpi 30.8 f 1.6 Itm long, width 2.0 f0.2 /em. Ora transversely elongated (length 2.7 f0.2 Itm, width 8.4 f0.9 pm). Apocolpium diameter 9.7 t 1.1 pm. Exine 1.6pm thick,slightly thicker at the apertures. Sexine reticulate. Muri 0.4 t0.1 /tm wide, simplibaculate. sometimes duplibaculate. Lumina 0.8 f0.2 pn, wide. Tectal part of muri 0.5 fo.l pm, baculate zone 0.5 k0.1 pm, foot layer 0.6 to.l pn thick. C. riiilleriii K. Schum. Herbarium material. Ibadan Olorunfemi, FHI. colporate, rarely 4-colporate; pleurotreme, sides convex-oblate spheroidal (P ca. 32.0k2.1 pm, E ca. 34.2fl.0 pm). Sexine subtectate. NPC: 345 (445). Colpi ca. 25.6f0.6 pm long, width 1.OfO.2 pm with a constriction in the middle. Ora transversely elongated (length 3.8 f1.0 Itm, width 9.1 fl.o pm), membranes granulate. Apocolpium diameter ca k1.3 pm. Exine ca. 1.5 /em thick. Sexine minutely reticulate. Tectal part of muri ca. 0.5 t O.1 pm, baculate zone ca. 0.4 fo.l Itm, foot layer ca pm thick. Hildcgardia barter; (Mast.) Kosterm. Fresh material. Ibadan Sowunmi 4. colporate; lobate or pcritreme-subprolate (P 38.7 f 2.0 pm, E 29.9 t 1.4 pm). Sexine subtectate. NPC: 345. Colpi 31.2k1.8 pm long, width 2.6f0.4 /em, becoming narrower towards the ends. Ora transversely elongated (length pm, width 6.4 If: 1.8 pm, often not sharply delimited at the lateral extremities. Apocolpium diameter 7.9 f 1.2 pm. Exine 2.9 /em thick at the apocolpia (1.9 pm thick at the mesocolpia). Sexine reticulate, slightly curvimurate. Muri 1.2 fo.l pm wide, discontinuous over small isolated areas, simpli- to triplibaculate. Lumina 1.5 f0.7 Itm wide, mostly elongated. Tectal part of muri 0.5 fo.l pm, ramibaculate apparently, especially at the apocolpia, baculate zone 1.6f0.2 /tm (0.6kO.I Itm at the mesocolpia), foot layer 0.8 ko.1 pn thick. hfansonia alrissiriia (A. Chev.) A. Chev. (PI. 9, Fig. 2). Herbarium material. Oyo Ahmed & Chizea, FHI. ponte; goniotreme, sides convcx, to peritreme-oblate (P 15 pm, E 22.4 pm). Sexine pertectate. NPC: 344. Pores nearly isodiametric (2.2 x 2.0 pm), annuli distinct and granulate (ca. 2.4 /tm wide). Apoporium diameter 1.24 pm. Exine ca. 1.1 /em thick. Sexine with a distinct LOpattern. Tectum ca. 0.3 pm, baculate zone ca. 0.4 pm, foot layer ca. 0.4 pm. Nesogordoriia papareri/rra (A. Chev.) R. Capuron (PI. 9, Figs. 3-4). Herbarium material. Ibadan Onyeachusim & Emiriogbon, FHI.

39 Polleri of Nigeriari plarits. I 183 Downloaded by [ ] at 23:10 21 November 2017 Pollen grains isopolar, radially synimctrical; 3- poratc; pcritrcmc-suboblatc (P 21.2 k0.7 pm, E colporate; peritreme-prolate spheroidal (P 21.6 k 26.4 f 1.2 pn). Scxinc subtcctatc. NPC: 344. Pores isodiametric (dianictcr 2.9 k0.5 In), pontopcrculatc. Apoporiurn diamctcr 16.2 f0.7 pm. Exinc 1.7 /im thick. Scxinc rcticulatc, slightly curvimurate in parts. Muri Iim wide, simplibaculatc, sometimes duplibaculate. Lumina 1.6 k0.5 pm widc, some with a few bacula. Tcctal part of muri 0.G ko.1 pm, apparently ramibaculatc in parts, baculate zone 0.6 k0.2 pm, foot laycr 0.5 ko.1 pm 0.9 I'm, E k0.5 pm). Sexine subtectate. NPC: 345. Colpi ca k 1.0 pm long, width ca. 1.2 f0.1 pm, with a slight mcdial constriction. Ora transversely elongated (lcngth ca. l.6ko.o pm? width ca. 4.0 k0.3 Itm?), often not clearly dcfincd. Apocolpium diamctcr 6.0 ko.8 pm. Exinc ca. 1.2 Icm thick. Sexine reticulate, curviniuratc in parts. Muri 0.4kO.l pm widc, distinctly thick. simplibaculate, duplibaculatc in parts. Lumina 0.8 f0.2 pm widc. Tcctal part ca pm, bacu- Pterygotu rriacrocarpa K. Schum. IIerbariuni matelate zone ca. 0.4 ko.1 pm, foot laycr ca. 0.5 ko.1 Iim rial. Abcokuta Joncs & Kay, FHI. thick. Pollcn grains isopolar, radially symmctrical; 3- colporate; goniotreme, sides convex-oblate spheroi- S. rragacaritha Lindl. Hcrbarium material. Abcokuta dal (P ca. 30 pm?, E 33.0 f 1.6 pm). Sexine subtcctate Kennedy 53, FHI. NPC: 345. Pollen grains isopolar,.radially symmetrical; 3- Colpi ca k3.2 pm long, width ca. 1.6 colporate; pcritremc-oblate sphcroidal (P 19.5 k0.6 k0.2 /tm pm, at and near the middle, narrower towards the ends. E 20.5 k0.9 pni). Sexinc subtcctatc. NPC: 345. Ora transvcrscly clongatcd (Icngth ca. 2.8 ko.8 Colpi indistinct. Ora transversely elongated, I'm, width ca. 7.0 ko.6,4pocolpiurn diameter (length 2*3 foe3 /'m, width 5.I k0.9 with a slight 12.1 k1.1 pm. medial constriction) latcral cxtrcmitics usually vaguc. Exinc ca. 1.9 I'm thick. Sexine reticulate. Muri Exine 1.7.pm thick. Sexine reticulate, curvimuratc 0.9 f0.2 /im widc, mostly duplibaculatc, simpli-or in parts. Muri 0.8 k0.l pm wide, discontinuous over small arcas, distinctly simplibaculatc. Lumina triplibaculatc in parts. Lumina 1.6 f0.6 /im wide, bacula prcscnt in some. Tcctal part of muri ca. 2.2f0.5 I'm wide, some with a few bacula. Tectal pm, apparently provided with vcrruca-likc part Of Oe5 ko.l baculate zone Oa6 koal processes, baculate zone ca. 0.6 ko.1,mi, foot layer loot layer 'O.' /Ini thick. ca. 0.7k0.1 pm thick. Stercrrlin oblotiga Mast. (PI. 9, Fig. 5) Herbarium material. Abcokuta Joncs & Kcay, FHI. colporoidatc; pcritreme-prolate spheroidal (P 27.5 f 1.4 Iim, E 25.2 f I.7.pm). Scxinc subtcctatc. NPC: 345. Colpi 19.4 k2.3 /tni long, width ca. 0.8 ko.1 pni, margins distinct (ca. 1.0 fo.l pm wide at the middle, gradually tapcring towards thc cnds). Ora not distinctly defined. Apocolpium diameter' 10.6 f0.2 I'm. Exinc ca. 0.9 pm? thick, stratification indistinct. Scxinc rcticulatc, curvimuratc in parts, apparcntly with supratectal verruca-like proccsscs. Muri 0.7 /im wide, sirnpli to duplibaculate. Lurnina 1.3 /mi wide, bacula prcscnt in some. S. rliiriopetala K. Schum Herbarium material. Oyo Emiriogbon, FHI: Triplocliifori sclcroxjlotr K. Schuni (PI. 9, Figs. 6-8). Frcsh material. lbadan Sowunmi 2. Pollcn grains isopolar, radially symmetrical; 3- porate; peyitreme-oblate (P 20.6 k 1.8 pm, E 28.8 f 1.4 pm). Sexine pertectate? NPC: 344. Porcs usually longitudinally clongatcd, somctimcs circular (Icngth -3.2 k0.5 pm, width 2.3 k0.3 pm), pontoperculatc, opercula not always clearly visible. Apoporium diameter 18.7 f 1.1 pm. Exinc 1.3 pm thick (2.3 /im thick at thc mcsoporia). Sexinc with a coarse LO-pattern, ;1 fine LO: pattcrn in the ccntral part of thc apoporia (po!ar vicw). The finc pattcrn is probably fornicd by small processes whose nature could not be definitely ascertained since they were not sccn in profilc. Tectum 0.4 k0.1 pm, baculatc zone 0.4 fo.l /im, ( /im at thc mcsoporia whcre they are stout and conrsc), foot layer 0.5k0.1 pm (0.6k0.1 pm thick at the mesoporia). Erdtman (1952, 1966) referred to the small central processes as "small spinuloid excres- Gratia 13

40 184 hf. A. Sowritit~ii cences". An electron microscopic study would obviously help to confirm this observation. Tiliaceae Creioia bicolor Juss. Herbarium material. Bauchi Jackson 531, FHI. colporate; goniotreme, sides convex, subprolate (P 45.3 /cm, E 29.8 pm). Sexine subtectatc. NPC: 345. Colpi 34.8 pm long, width ca. 2.8 pni at and near the middle, gcntly narrowing gradually towards the ends. Ora transversely elongated (Icngth ca. 2.7 pm, width ca. 9.4 pm) often not distinctly demarcated, particularly at the lateral extremities. Apocolpium diameter ca pm. Exinc 1.7 pm thick. Scxine reticulate. Muri 0.8 /em widc, simpli- to duplibaculate. Luniina 1.4 /em wide, occasionally with few bacula. Tectal part of muri 0.5 pm, undulating, appears to bear verruca-like processes (?), baculatc zone 0.6 /tm, foot layer 0.6 pm thick. G. coriacea Mast. Herbarium material. Benin Daramola 6: Emiriogbon, FHl. Pollen grains similar in general to those of C. bicolor (only the differences arc notcd here) peritreme; prolate (P 28.3 pm, E 20.0 pm). Colpi 22.0 pm long, '1.5 Itm wide. Ora length 2.3 pm, width 6.6 Itm. Exine 1.5 pm thick. Muri 0.5 Itm widc. Lumina 1.0 pm wide, no bacula seen. Tectal part of muri 0.4'pm, without verruca-like processes, foot layer 0.5 I'm. G. ittollis Juss. (PI. 9, Fig. 9). Herbarium material. Ilorin Macaulay, FHI. Pollen grains similar in general to those of C. biculur (only the differences arc mentioned here) prolate (P 50.7 pm, E 31.6 pm). Colpi 41.0 pn long, 2.3 pm widc, with a medial constriction. Ora length 4.1 pm, width 9.0 pm. Muri 0.9 Icm widc. Lumina 1.6 pm wide. Baculate zone 0.7 /em. foot layer 0.5 Itm. Ultrinceoe Celtis broictiii Rendle Herbarium matcrial. Ibadan Onyeachusim & Binuyo, FHI. porate, rarely 4-porate; goniotreme, sides convex, or peritreme-suboblate (P pm, E 19.5f 0.8 pm). Scxine pertectate? NPC: 344 (444). Pores isodiametric or slightly elongated longitudinally (length 2.6 k0.3 /tm, width 2.4 f0.3 pm), annuli distinct and granulate (0.6 fo.l /tm wide). Apoporium diameter 13.4 f 1.4 /ern. Exine ca. 1.1,mi thick, stratification indistinct. Sexine LO-patterned. C. iutegrifolia Lam. (PI. 9, Fig. 10). Herbarium material. Okeigbo Tamajing & Sawyerr, FHI. Pollen grains very similar to those of C. broiwii (only the few minor differences mentioned here). NPC: 344. Pores (length 2.8 prn, width 1.9 pm) more clongated longitudinally, annuli 0.8 pm wide. Apoporium diameter 12.6 Itm. Exine 0.1) /tm thick. Utrrbellijerne Stegartotacrriu aralincen Hochst. Herbarium material. Zaria Low 73, FHI. colporate; lobatc-prolate (P 27.5 pm, E 14.8 pn). Sexine subtcctate. NPC: 345. Colpi 22.6 pni long, widest at and near the middle, tapering sharply towards the ends (width not discernible). Ora seem rounded (dimensions difficult to ascertain). Apocolpium diameter ca. 4.8 pm. Exine 1.2.mi thick. Sexine minutely reticulate. Tectal part of muri 0.3 /em, baculate zone 0.4 pm, foot layer 0.5 Itm. Verhetmceae Vitex dooninria Sweet Herbarium material. Jos Olorunfemi, FHl. colpate; lobatc-oblate spheroidal (P 25.7 f 1.8 pm, E 25.9 f 1.2 pn). Sexjnc subtcctate. NPC: 343. Colpi ca. 17.6f1.4 Icm long, width ca. 1.4f0.1 /em. Apocolpium diameter 8.0 fo.l pm. Exine 2.0 pm thick (thinner at the colpi). Sexine reticulate, reticulation finer at apocolpia than at mesocolpia. Muri pm wide, distinctly simplibaculatc. Lumina 0.7 fo.l pm wide. Tectal part of muri 0.6 fo.l pm, baculate zone /em, foot layer 0.9 f0.1 pm thick. GENERAL COMMENTS The degree of intraspecific variability in pollen grain form found in the prcscnt material is very striking and noteworthy. It corroborates Guinet's (1962) remark, based on his study of the pollen of tropical

41 Asian plants, that such variability seems widespread in the tropics. Intraspecific variability was noted in 30% of the Nigerian species investigated here. The variations involve such features as. tetrad type, shapc, size, aperture number, and polarity. A few examples will now bc highlighted. In Atrnotridirirrr nrannii (Annonaceae) where the discrete pollen unit is a tetrad, these tetrads may be tetragonal, rhomboidal, or dccussate. Diospyros crassiflora (Ebenaceae) has both oblate sphcroidal and prolate spheroidal grains. Size and shape variations are always closely correlated, the morc prolate grains being larger than the less prolatc ones. Two or more aperture types may be found in one species. Diospyros crassiflora has both 3- and 4- colporatc grains, while Hyttietiosfegia afzelii (Caesalpinaceac) has 3- and 2- as wcll as 4-colporate ones, and Sytitphonia globrilvera (Guttiferae) has 4-5- and 3-pororatc grains. Finally, in Latrtrea nricrocurpa (Anaurdiaceac) and Dichrostaclrys citierea (Mimosaceae), some grains arc syncolpate while others are not. Further studies may reveal whether such variations arc genetically controlled, or are due to internal environmental factors (within the anther locule). There are at least two implications of this phenomenon. Firstly, in pollcn morphological studies of extant spccies, it is essential to examinc a sufficiently large number of grains from any one particular species, in order to obtain as complete a picture as possible of the array of types within that species. Sowunmi (1967), in this context, indicated that at least 500 grains should be examined.. Secondly, in pollen analytical studies, it is important to be aware of probable intraspecific variability, so that false determinations are not made, from assigning variants of one spccies to two or more different ones, or failing to recognise the identity of a particular variant in the absence of the normal type. TERMINOLOGY USED Amb: Outline of a pollen grain vieived with one of the poles exactly uppeimost. Apoporium: Area at a pole, delimited towards the equator by the polar limits of the mesoporia. Ektexine: The outer of the two main layers of a typical cxine (-exine-l). Endcxine: The inner of the two main layers of a typical exine (= exine-2). Foot layer: The innermost Ihyer of the ektexine (= nexine-i). Polleti of Nigeriatr platits. Z 185 Goniotreme: Pollen grains with angular amb, with the centre of the apertures ai the angles. Heterobrochate: With brochi off distinctly different sizes. Intectate: Pollen grains without a tectum or tectal areas. LO-pattern: Any pattern which at high adjustment of the microscope appears as light islands separated by dark channels and on loner adjustment presents a reverse picture. Negatively reticulate: Pollen grains with sexine isles separated from one another by a network of grooves. NPC: N: Number, P: Position, C: Character of the apertures. OL-pattern: The reierse of an LO-Pattern. Pcritreme: Pollen grains with the centre of each individual aperture situated on a circular amb. Pertectate: Pollen grains with a continuous, uninterrupted (as seen by means of an ordiniry microscope) tectum. Pleurotreme: Pollen grains with an angular amb. with the centre of each individual aperture situated halfway betneen two adjacent angles. Pontoperculate: Said of elongate apertures where the apical parts of the opercula merge with the exine surrounding the apertures. Scrobiculate: Reticulate pollen grains with very small circular lumina. Sexine: The outer sculptured part of the exine, comprising two layers-tectum and bacules. Subtectate: Tectate, but neither pertectate nor intectate. Vcrmiculate: Pollen grains with grooves like norm tracks. ACKNOWLEDGEMENTS I would like to express my deep gratitude to the Director of the Federal Department of Forest Research, Ibadan. and his herbarium staff for permission to collect, and ready help with the collection of polliniferous materials from their herbarium. Thanks are also due to Madame M. Van Campo and M. J. Maley, C.N.R.S.. Montpellier. France. for supplying.some pollen slides, under an exchange programme. My thanks go to hfr Omotoso, my assistant, for the preparation of many pollen slides. and to my colleagues hfr R. Osoba. Mrs J. Ajayi and hfiss M. Oladipo for help with the photomicrographs. Finally 1 would like to thank Miss L. Falegan and Mrs A. A. Ketiku for preparing the manuscript. REFERENCES Assemien, P Pollen fossile de Rhizophora?i bogue (Basse Vallte du Stntgal). - Pollen Spores 11: Bronckers, F Palynologie Africaine VII. - Bull. Inst. fr. Afr. noire str. A. 29: Bronckers, F. & De Keyser, In: Palynologie Africaine. V. Bull. Inst. Fr. Afri. Noire scr. A, 26 (4). Canright, J. E Phylogeny of some Ranalcan families. - Grana Palynol. 4: Clarke, R. T Peregrinipollis nigericus a new palynomorph from the Upper Tertiary of Nigeria. - Grana Palynol. 6: Clarke, R. T. & Frederiksen, N Some new sporomorphs from the Upper Tertiary of Nigeria. - Grana Palynol. 8: Grotto 13