WHMF121 Session Eleven Flowers

WHMF121 Session Eleven Flowers Endeavour College of Natural Health endeavour.edu.au 1

Todays Topic - Flowers o Anatomy of a flower Various types of flowers o Inflorescences Various types of inflorescences o Practical session: Dissect some flowers Endeavour College of Natural Health endeavour.edu.au 2

Amborella is thought to be the descendant of the first flower (Penn State, 2012, http://www.flickr.com/images/pennstatelive/11456508663/sizes/l/) Endeavour College of Natural Health endeavour.edu.au 3

Flowers o Flowers are the reproductive organs of the Angiosperms, the flowering plants. o The typical flower grows on a stem called the pedicel, which widens at the end to form the receptacle. o The receptacle is not always easy to distinguish. o It is the area from which the flower part grows. Receptacle Pedicel https://commons.wikimedia.org/wiki/categor y:flower_diagrams#mediaviewer/file:cherr y_blossom.svg Endeavour College of Natural Health endeavour.edu.au 4

Flowers o Apart from the pedicel and receptacle, there are usually four parts to a flower: 1. Calyx Outermost parts 2. Corolla Petal arrangements 3. Androecium Male arrangements 4. Gynoecium Female arrangements Endeavour College of Natural Health endeavour.edu.au 5

o o o o Calyx The calyx is the outermost part of the flower and is made up of sepals. The number of sepals varies from species to species but most species have 3-5 sepals. Sepals are usually green, they enclose and protect the flower as a bud. The sepals may remain attached to the receptacle after the flower opens or they may fall off as the flower opens. Sepals Endeavour College of Natural Health endeavour.edu.au 6

Corolla o Inside the calyx is the corolla. o The corolla consists of petals o Usually the most recognisable parts of the flower. o The number of petals is also variable between species. o There is often the same number of petals as sepals, or the number of petals is a multiple of the number of sepals. o Petals play an important role in plant reproduction as their colour and scent attract birds or insects which carry pollen. o The calyx and corolla together are called the perianth. Petals Endeavour College of Natural Health endeavour.edu.au 7

Corolla o In some flowers the sepals or petals may look similar. o It is difficult to distinguish the sepals from the petals in this photo. o In this case the perianth parts are called tepals. o This is common in the Liliaceae families. (https://commons.wikimedia.org/wiki/lilium#mediaviewer/fil e:lilium_%27red_velvet%27_04.jpg) Endeavour College of Natural Health endeavour.edu.au 8

Androecium o Inside the petals are the stamen consisting of the anther supported by the filament. o There is a huge range in the number of stamens from 1 or 2 to 20 or more. o Androecium is the term used to describe the stamens collectively. o (Andros=male; oecium=house/place) o So androecium is the male place. Anther Filament Endeavour College of Natural Health endeavour.edu.au 9

Multiple stamen of a flowering gum (Photo with permission - Wendy Williams) Endeavour College of Natural Health endeavour.edu.au 10

Androecium o Stamen are the male reproductive organs of the plant. o Pollen grains are formed in the anther and released to be carried to another flower. Pollen is transported by wind, birds or insects. o Some flowers that rely on birds or insects for pollination encourage these animals by producing nectar in glands deep inside the flower. o When the animal tries to reach the nectar it rubs against the anthers and pollen sticks to it. o When the animal visits another flower of the same species the pollen is rubbed off onto the female part of that flower. Endeavour College of Natural Health endeavour.edu.au 11

Flowers Notice the grains of pollen sticking to the hair on this honey bee. This will be transferred to other plants as it goes about its business pollinating up to 100 different flowers a day. Another example of why the flowering plants are so highly evolved. (http://en.wikipedia.org/wiki/file:bees_collecting_pollen_cropped.jpg Endeavour College of Natural Health endeavour.edu.au 12

Gynoecium o In the centre of the flower is the gynoecium - gyno=female Gynoecium is the female place. o The gynoecium is made up of carpels Female reproductive organs of the plant. o Each carpel consists of: Ovary is at the bottom of the carpel - will develop into fruit. Style is a column of varying length extending above the ovary Stigma is at the tip of the style. Stigma Style Ovary Endeavour College of Natural Health endeavour.edu.au 13

Flowers A cross section of a typical gynoecium (http://commons.wikimedia.org/wiki/file:tulip01.jpg) Endeavour College of Natural Health endeavour.edu.au 14

Flowers o When a bird or insect carrying pollen goes to another flower in search of nectar, it brushes against the stigma. o The surface of the stigma is sticky to catch pollen. o The pollen grows down into the ovary and fertilises the ovules. o The number of carpels varies from 1 to many. o If there is more than 1 carpel they may be separate or joined together. Endeavour College of Natural Health endeavour.edu.au 15

Cross section of a Rose Hip - notice the swollen ovary with seeds that form the hip or fruit (wiki/commons) Endeavour College of Natural Health endeavour.edu.au 16

o TED Talk on pollination TED Talk Video o https://www.ted.com/talks/jonathan_drori_the_beautiful_tricks_of_flowers Anthers https://commons.wikimedia.org/wiki /Category:Anthers#mediaviewer/Fil e:2012-04-03_16-43-53-amaryllissp.jpg Endeavour College of Natural Health endeavour.edu.au 17

Flower Variations o Flowers are the most individual and distinctive parts of the plant. o It is usually necessary to confirm flower characteristics in order to identify a species. Distinctive features of flowers include: Shape Presence, or absence of parts Relationship between parts Fusion of parts Position of parts (Tan, 2013) Endeavour College of Natural Health endeavour.edu.au 18

Shape o The shape of flowers varies from species to species. o Basically there are two types of symmetry in flowers Actinomorphic flowers have radial symmetry Zygomorphic flowers have bilateral symmetry. o The symmetry of flowers is important for the recognition of certain plant families. Endeavour College of Natural Health endeavour.edu.au 19

(Clarke & Lee, 1987) Endeavour College of Natural Health endeavour.edu.au 20

Can you tell which is Zygomorphic? Sego Lily (http://en.wikipedia.org/wiki/file:sego_lily_cm.jpg) Lamium purpureum (http://commons.wikimedia.org/wiki/file:lamium_purpur eum_enbla10.jpg Endeavour College of Natural Health endeavour.edu.au 21

Absence of Flower Parts Some flowers have one or more of the basic four parts missing. In some species there is no calyx in the flower, in others the corolla may be absent. A flower with no sepals or petals is said to be naked. Sterile outer flowers, fertile inner flowers. Endeavour College of Natural Health endeavour.edu.au 22

Absence of Flower Parts An example of very small inconspicuous sepals Callistemon spp. (Bottlebrushes) http://en.wikipedia.org/wiki/file:red_bottle_brush.jpg Endeavour College of Natural Health endeavour.edu.au 23

Absence of Flower Parts An example of no calyx Eschscholtzia californica (Californian Poppy) (http://commons.wikimedia.org/wiki/file:california_pop py_eschscholzia_californica_03.jpg Endeavour College of Natural Health endeavour.edu.au 24

Absence of Flower Parts The sterile outer flowers of Viburnum opulus. (Crampbark) http://en.wikipedia.org/wiki/file:viburnum_opulus_flowers.jpg Endeavour College of Natural Health endeavour.edu.au 25

Absence of Flower Parts Sterile flower - Hortensia spp. (Hydrangea) Think about this, how would they reproduce? (https://commons.wikimedia.org/wiki/file:sterile_flowers_of_hydrangea_macrophylla_f._hortensia.jpg) Endeavour College of Natural Health endeavour.edu.au 26

Absence of Flower Parts o Flowers with no gynoecium/carpels are male flowers o Flowers with no androecium/stamens are female flowers. o Plants with no sex organs at all are sterile or neutral. (Tan, 2013) o When a species has separate male and female arrangements arrangements, they may be on: Same plant - plants are said to be monoecious (one place) eg. Zea mays (corn), also melons, pumpkins etc Different plants - plants are said to be dioecious (two places) eg Carica papaya, (papaya), also Ginkgo biloba, Cycas spp., & Salix spp. (willows) Endeavour College of Natural Health endeavour.edu.au 27

Absence of Flower Parts Example of monoecious (1 place) eg. Zea mays (corn). Male corn tassles' on top dust the silks below on the plant Female silks growing half way down the plant, which will develop into corn Endeavour College of Natural Health endeavour.edu.au 28

Absence of Flower Parts Some species Carica papaya can have male or female flowers on different trees and are dioecious (2 places) Male flower hanging with pollen no gynoecium Female flower with stigma no androecium Endeavour College of Natural Health endeavour.edu.au 29

Fusion of Parts o In many flowers the flower parts are joined together in some way. o The way their petals, sepels, stamen and carpels are joined. o There are a number of terms used to describe this and there are 2 categories: 1. Fusion of like parts 2. Fusion of unlike parts Endeavour College of Natural Health endeavour.edu.au 30

Fusion of Parts 1. Fusion of like parts: Fusion of like petal parts o They are said to be connate - fused or joined. o e.g. the petals of Digitalis purpurea (foxglove) - instead of being separate are joined together into a corolla tube. Endeavour College of Natural Health endeavour.edu.au 31

Fusion of Like Parts Digitalis purpurea (Foxglove) - fused petals Think about this plants Latin name - can you work it out? (Photograph with permission of Wendy Williams) Endeavour College of Natural Health endeavour.edu.au 32

Flowers The connate corolla of Ipomoea purpurea (Morning Glory) (http://commons.wikimedia.org/wiki/file:ipomoea_purpurea_2400px.jpg) Endeavour College of Natural Health endeavour.edu.au 33

Fusion of like parts: Fusion of Parts o Other parts may be connate; sepals, stamens (anther or filament) and carpels. o When there are connate carpels the gynoecium is said to be syncarpous and the carpels will all be surrounded by the one ovary wall. e.g. Lilium sargentiae How many carpels do you think there are? (http://commons.wikimedia.org/wiki/file:liliumsargentiae.jpg) Endeavour College of Natural Health endeavour.edu.au 34

Fusion of Parts o If there is only one ovary wall, the best way to tell how many connate carpels there are is to cut a transverse section of the ovary and see how the ovules are arranged. o If there is only one loculus then the number of carpels may be reflected in the number of lobes or branches of the stigma or style stigma. Endeavour College of Natural Health endeavour.edu.au 35

Fusion of Parts o The placentation (points of attachment of the ovules) can also indicate the number of carpels. o When there is more than one carpel and they are free (not connate) the flower is said to have an apocarpous gynoecium. e.g. Rubus idaeus (raspberry). o If the ovules seem to be in separate compartments or loculi each loculus corresponds to one carpel. Endeavour College of Natural Health endeavour.edu.au 36

Fusion of Parts Two examples from the Rosaceae family which have an apocarpous gynoecium Crataegus monogyna Rosa arvensis Endeavour College of Natural Health endeavour.edu.au 37

Fusion of Parts Examples of different carpel variations Endeavour College of Natural Health endeavour.edu.au 38

Fusion of Unlike Parts 2. Fusion of unlike parts o If parts of flowers are fused to different parts (e.g. sepals joined to petals) they are said to be adnate. o Quite frequently the calyx, corolla and androecium are adnate forming a floral tube. Can you see which parts of this Hibiscus rosasinensis are adnate? (http://en.wikipedia.org/wiki/file:hibiscus_flower_tz.jpg) Endeavour College of Natural Health endeavour.edu.au 39

Position of Flower Parts This refers to the relative position of the ovary and other flower parts. If the ovary is below the point where the other flower parts start it is an inferior ovary. Inferior ovaries occur in epigynous flowers because the flower parts grow from above the ovary (epi=above, gynous = gynoecium). Endeavour College of Natural Health endeavour.edu.au 40

Position of Parts Label these ovary positions (https://commons.wikimedia.org/wiki/file:ovary_position.svg) Endeavour College of Natural Health endeavour.edu.au 41

Position of Parts If the ovary is above the point where the other flower parts start it is a superior ovary. In this case both the ovary and the other flower parts grow from the receptacle. The flowers are said to be: perigynous (peri=about or around or enclosing the gynous) hypogynous (hypo=below the gynous) Endeavour College of Natural Health endeavour.edu.au 42

Position of Parts In hypogynous flowers the flower parts start from the receptacle below the ovary. In perigynous flowers a floral tube is separate from but extends part of the way up the length of the ovary. A half inferior ovary is an inferior ovary with the top of the ovary protruding beyond the point where the other flower part starts. Endeavour College of Natural Health endeavour.edu.au 43

(Clarke & Lee, 1987) Endeavour College of Natural Health endeavour.edu.au 44

Inflorescence A single flower on a stem is called a solitary flower. An inflorescence is a group of flowers growing from the same stem. (Photos with permission- Wendy Williams) Endeavour College of Natural Health endeavour.edu.au 45

Inflorescence o Flowers grow in an inflorescence according to two basic patterns: Racemose New growth keeps growing at the tip while the older flowers develop behind it. Cymose Oldest flower is at the growing tip of the plant stem, while the new growth develops behind it. Endeavour College of Natural Health endeavour.edu.au 46

Inflorescences Racemose inflorescence Cymose inflorescence Desmodium heterocarpon (Valke, n.d., http://www.flickr.com/images/dinesh_valke/1461963475/) Pimpinella major (http://en.wikipedia.org/wiki/file:apiaceae_-_pimpinella_major-1.jpg) Endeavour College of Natural Health endeavour.edu.au 47

Racemose Inflorescence Types of racemose inflorescence: o Raceme the simplest racemose inflorescence. Flowers grow on pedicels in order behind the growing tip of the plant stem. o Spike a raceme with sessile flowers (flowers that have no pedicels). o Corymb is a raceme where the pedicels keep growing so that the flowers are all at the same level. o Panicle is more complicated but is like a stem with a series of racemes growing laterally from it. Endeavour College of Natural Health endeavour.edu.au 48

Racemose Inflorescence Corymb Raceme Spike Panicle https://commons.wikimedia.org/wiki/inflorescence Endeavour College of Natural Health endeavour.edu.au 49

Cymose Inflorescence o This pattern of growth results in the first flower growing at the tip of the plant stem. o Stem growth stops at that point, and continues from the node behind the tip. o Sympodial branching results in cymose inflorescences. o In practice sympodial branching is not always easy to recognise when examining a plant specimen. o The continued growth of the stem from the node behind the flower often appears to be growth continuing at an angle from the tip of the plant stem. Endeavour College of Natural Health endeavour.edu.au 50

Cymose Inflorescence There are different types of cymose inflorescence: 1. Simple cyme: the node below the flower grows another flower (or two) 2. Compound cyme: the stem node keeps growing as a stem and repeats the process of terminating in a flower. https://commons.wikimedia.org/wiki/inflorescence#mediaview er/file:gevorkt_bijscherm.jpg Endeavour College of Natural Health endeavour.edu.au 51

Cymose Inflorescence o Plants in the Boraginaceae family (e.g. Symphytum officinale (comfrey), Borago officinale (borage) have cymose inflorescences that grow in a spiral. (Tan, 2013) (Guerin, n.d., http://www.flickr.com/images/biodivers3873010771/8776123917/ Endeavour College of Natural Health endeavour.edu.au 52

Cymose Inflorescence Sphenosciadium capitellatum http://en.wikipedia.org/wiki/file:sphenosciadium_capitellatum_rangers_buttons.jpg Endeavour College of Natural Health endeavour.edu.au 53

Cymose Inflorescence 3. Umbels and Capitula: o In some cases the stem growth ends with many flowers apparently at once. o If the flowers have pedicels the inflorescence is called an umbel. o If the flowers are sessile (have no pedicels) the inflorescence is called a capitulum or head https://commons.wikimedia.org/wiki/inflorescence#mediaviewer/ File:Inflorescence_morphology_simple_umbel_determinate.png Endeavour College of Natural Health endeavour.edu.au 54

Cymose Inflorescence o Umbels and heads can be classified as racemose or cymose according to how the flowers grow. When the flowers grow from the outside first, the umbel or head is racemose. When the flowers grow from the inside first, it is a cymose umbel or head. o Younger flowers are usually smaller than older flowers. Therefore racemose umbels and heads have larger flowers/florets around smaller ones. o Cymose umbels and heads have smaller ones around larger Endeavour College of Natural Health endeavour.edu.au 55

Inflorescence of Apiaceae o The Apiaceae family is characterised by small flowers arranged in simple or compound umbels o A compound umbel is formed when the stem branches and each branch forms an umbel Astrantia major http://en.wikipedia.org/wiki/file:plantsinarvenbul1400m.jpg Aegopodium podograria (Gaither, n.d., http://www.flickr.com/images/jimsf/2663690329/ Endeavour College of Natural Health endeavour.edu.au 56

Inflorescence of Apiaceae Compound Umbel Simple Umbel https://commons.wikimedia.org/wiki/inflorescence#mediaviewer/file:sa mengesteld_scherm.jpg Endeavour College of Natural Health endeavour.edu.au 57

Inflorescence of Asteraceae o Daisies look like a single flower but if you look closely you will see that they are lots of tiny flowers (called florets) that share a single receptacle. o Around all the florets are little green bracts. o This kind of inflorescence or group of flowers is called a capitulum or head since the flowers are sessile. o The bracts are known as involucral bracts. o The florets apart from having no pedicel, have calyx, corolla, androecium and gynoecium the same parts as normal flowers Endeavour College of Natural Health endeavour.edu.au 58

Inflorescences A magnification of the individual florets with the non ripened fruit of Helianthus annuus (Sunflower) (Halkett, 2011, http://www.flickr.com/image s/kitkath-ruiz/8109325175/ Watch the video: https://www.youtube.com/watch?v=ykxxer4sbrc Permission given by Neil Bromhill www.rightplants4me.co.uk Endeavour College of Natural Health endeavour.edu.au 59

Inflorescences o Beautiful video about pollination: o http://www.ted.com/talks/louie_schwartzberg_the_hidden_beauty_of_pollina tion Endeavour College of Natural Health endeavour.edu.au 60

Practical Session o Draw a flower. Cut lengthwise, draw. o Label pedicel, sepals, petals, anther, filament, stigma, style, ovary. o Is your flower actinomorphic or zygomorphic? o Is the ovary superior or inferior? o Are there any fused parts? If so, what? Endeavour College of Natural Health endeavour.edu.au 61

Label This Diagram o Label: o pedicel o sepals o petals o anther o filament o receptacle o stigma o ovary o where would you find the style? 8 7 6 https://commons.wikimedia.org/wiki/category:flower_diagram s#mediaviewer/file:bluete-schema.png Endeavour College of Natural Health endeavour.edu.au 62

Practical Session o Draw an inflorescence. Cut lengthwise, draw. o Label receptacle, involucral bracts, florets. What type of head is it? o Remove a single floret (or tubular and ligulate florets). o Draw ovary/ovaries, pappus, anther tube, style branches, ligule. o Is the ovary superior or inferior? Endeavour College of Natural Health endeavour.edu.au 63

Next Week o Field Trip Make sure you know where to meet Time Bring note books, cameras, water, hats and wear practical shoes for walking Endeavour College of Natural Health endeavour.edu.au 64

Suggested Readings Capon, B. (2010). Botany for gardeners (pp. 195-216). Portland, OR: Timber Press. Clarke, I., & Lee, H. (1987). Name that flower: The identification of flowering plants (pp. 7-34). Carlton, Vic: Melbourne University Press. Mauseth, J. (2014). Botany: An introduction to plant biology (5 th ed.). (pp. 244-5, 248-63). MASS: Jones & Bartlett Publishers. Tan, E. (2004). Herbal preparations laboratory manual (pp. 41-52). Victoria, Australia: Northern Melbourne Institute of TAFE. Endeavour College of Natural Health endeavour.edu.au 65

References Clarke, I., & Lee, H. (1987). Name that flower: The identification of flowering plants. Carlton, Vic: Melbourne University Press. Tan, E. (2004). Herbal preparations laboratory manual. Preston, VIC: Northern Melbourne Institute of TAFE. Tan, E. (2013). Botany of the flowering plants (4 th ed.). Preston, Vic: Northern Melbourne Institute of TAFE. Wohlmuth, H. (1992). An introduction to botany and plant identification. (2 nd ed.). Lismore, NSW: MacPlatypus Productions. Endeavour College of Natural Health endeavour.edu.au 66

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