Flower = a short, determinate shoot bearing highlymodified leaves, some of which are fertile (i.e.,bearing either microsporangia or megasporangia),with the megasporangia in carpels

Review: flowers and flower parts

Flower• REPRODUCTIVE STRUCTURE OF ANGIOSPERMS –

Evolutionary requirement to reproduce by sexual means. Pollen transfer and seed dispersal needed.

• MODIFIED FOLIAR APPENDAGES – all function together to form the reproductive organ known as the FLOWER.

• MODIFICATIONS OF LEAVES – All floral organs are modified

LEAVES. Four terminal WHORLS of modified leaves:

- Two outermost whorls are sterile (non-meiotic tissues)- Two innermost whorls (sporophylls) are “fertile” with

tissues capable of undergoing meiosis

• SPOROPHYLLS – those modified leaves with meiotic capacity.- Microsporophylls – stamens – produce pollen in

anthers- Megasporophylls – carpels – produce eggs in ovules

Figure 4.16 from the text

Floral Parts: Major whorls

pistil - gynoecium

stamens - androecium

petals - corolla

sepals - calyx

receptacle

Figure 4.21 from the text

Superior, Hypogynous

Superior, Perigynous

Floral cup (= hypanthium)present but not fused with the gynoecium

Inferior = Epigynous

Hypanthium fused togynoecium, sometimesextending above it intoa conspicuous floral tube.

In a few special cases, the Cactaceaebeing the main example,epigynous flowers havea hypanthium derived mainly from receptacletissue.

Rosids – Part 4:Eurosids II - Brassicales - Malvales - Sapindales

Spring 2010

“Lower”Core tricolpates

Rosids

(Eurosids II)

(Eurosids I)

“Basal” rosids

Figure 9.3 from the text

Core Eudicots: The Rosids Lecture 4“Basal” Rosids:

Order VitalesEurosids I (Fabids):

Order MalpighialesOrder CucurbitalesOrder FabalesOrder RosalesOrder FagalesOrder Myrtales

Eurosids II (Malvids)Order Brassicales

Brassicaceae - MustardsOrder Malvales

Malvaceae – Mallows, cotton, chocolateOrder Sapindales

Sapindaceae – Maples, lycheeRutaceae – CitrusAnacardiaceae – Mangoes, cashews, poison ivy

Eurosids II:

Brassicales: Brassicaceae(‘Cruciferae’ - The Mustard Family)

• Cosmopolitan, most diverse in the Mediterranean region, SW Asia, and western North America

• Herbs, shrubs or trees; (sometimes herbs); glucosinolates (mustard oils) present in all taxa

• Diversity: 4,130 species in 356 genera• Flowers: Receptacle prolonged into a gynophore (short to long);

Sepals 4; petals 4 (cruciform); stamens 6, all + equal or 2 shorter and 4 longer (tetradynamous); carpels usually 2, connate, superior ovary; fruit is a berry or capsule; if dehiscing by splitting into 2 valves, a silique

• Significant features: 4-merous flowers forming a cross; often pioneers after disturbance

• Special uses: Many important food plants – cabbage, broccoli, cauliflower, brussels sprouts, kohlrabi (Brassica oleracea), turnip (Brassica rapa), mustards (Brassica spp.), horseradish (Armoracia rusticana), and a wide range of ornamentals

• Required taxa: Brassica

Brassicaceae

cruciform petals

silique - silicletetradynamous stamens

Arabidopsis thaliana

The model plant ofchoice for much ofmolecular biology.

-annuals or biennials-at least the lower leaves deeply pinnatifid, lyrate or pinnate-racemes without bracts-sepals erect during anthesis-petals yellow-ovary and silique with a prominent beak

Brassicaceae: Brassica

Brassicaoleracea

Eurosids II:

Malvales: Malvaceae(The Mallow Family)

• Cosmopolitan• Trees, shrubs, lianas or herbs; vegetative parts with mucilage;

leaves palmately veined and lobed or palmately compound• Diversity: 2,330 species in 204 genera• Flowers: Sepals & petals 5; stamens 5 to many,

monadelphous or polydelphous; carpels 2 to many, connate, superior ovary; fruit usually a loculicidal capsule, also berry, nut, schizocarp, or drupe

• Significant features: flowers often associated with conspicuous bracts forming an epicalyx; nectaries of densely packed, multicellular glandular hairs, usually on sepals

• Special uses: cotton (Gossypium), cacao or chocolate (Theobroma), durian (Durio), balsa wood (Ochroma); many ornamentals, e.g. hibiscus (Hibiscus)

• Required taxa: Hibiscus, Gossypium

Polydelphous stamens Monadelphous stamens

Malvaceae

Malvaceae: Hibiscus -herbs or shrubs-epicalyx of a circle of several bractlets-filament column bearing anthers for much of its length-styles distinct-fruit a 5-locular loculicidal capsule-seeds 2-several per locule, kidney-shaped

Malvaceae: Gossypium

-subshrubs to shrubs-epicalyx of 3-5-7 large, cordate, toothed bracts-styles united-fruit a 3-5-locular loculicidal capsule-seeds + globular, often with hair (lint)

Eurosids II:

Sapindales: Sapindaceae(The Maple Family)

• Mainly tropical and subtropical, a few diverse in the temperate zone (e.g., Acer, Aesculus)

• Trees, shrubs or lianas with tendrils• Diversity: 2,215 species in 147 genera• Flowers: Usually unisexual; sepals & petals 4-5, petals often

clawed, with more or less basal appendages adaxially; usually an extrastaminal nectar disk present; stamens 8 or fewer (rarely up to 12), filaments usually hairy or papillose; carpels 2 or 3, connate, superior ovary; fruit a capsule, berry, or schizocarp; seeds with a deep fold or pocket in the seed coat

• Significant features: cyclopropane amino acids• Special uses: lumber, maple syrup (Acer saccharum); many

ornamentals; tropical fruits (longan, lychee, rambutan)• Required taxa: Acer

Sapindaceae phylogeny

SAP

HIPP

ACER

SAP

SAP

SAP

SAP

SAPChemistryAppendaged petalsCurved embryo w/ seed coat “pocket”8 or fewer stamensEtc.

Sapindaceae: Acer

-trees or sometimes shrubs-leaves opposite, simple and palmately lobed, rarely pinnately or palmately compound-calyx usually 5-lobed-petals 0 or as many as the calyx lobes-ovary with 2 connate, winged carpels, 2 ovules per carpel-fruit a schizocarp, splitting into 2 samaroid mericarps

Eurosids II:

Sapindales: Rutaceae(The Citrus Family)

• Nearly cosmopolitan, primarily tropical to subtropical• Trees or shrubs, sometimes with thorns, spines or prickles• Diversity: 930 species in 155 genera• Flowers: Sepals & petals 4 – 5; stamens 8-10; carpels 4-5 to

many, connate, superior ovary; axile placentation; fruit a drupe, capsule, samara, cluster of follicles or modified berry with leathery, glandular rind (i.e., hesperidium in Citrus).

• Significant features: Aromatic oils chemically complex; simple or compound leaves with pellucid dots containing aromatic ethereal oils

• Special uses: many desirable fruits - oranges, lemons, limes, tangerine, grapefruit (Citrus), kumquat (Fortunella), several ornamentals, e.g. cork tree (Phellodendron)

• Required taxa: Citrus

Rutaceae: Citrus

-leaves apparently simple, of 1 leaflet-ovary compound, entire or only slightly lobed-fruit a hesperidium

Eurosids II:

Sapindales: Anacardiaceae(The Sumac or Cashew Family)

• Mainly pantropical; some in temperate regions• Trees, shrubs, or lianas; well-developed resin canals; leaves

usually pinnately compound & alternate• Diversity: 600 species in 70 genera• Flowers: Usually unisexual; Sepals & petals 5; stamens 5-

10; carpels usually 3, connate, but usually only 1 carpel fully developed and fertile; superior ovary; fruit is a drupe, frequently flattened and asymmetrical

• Significant features: Medically-important – poison-ivy (Toxicodendron radicans) and other taxa (Rhus, Metopium) cause contact dermatitis due to oils in plant tissues. Some individuals are even allergic to ‘edible’ taxa.

• Special uses: mangoes (Mangifera indica), cashews (Anacardium occidentale), pistachio (Pistacia vera); some ornamentals, e.g. Sumac (Rhus) and smoke-tree (Cotinus)

• Required taxa: Toxicodendron

Anacardiaceae: Toxicodendron

T. radicans - Poison Ivy

-resins toxic-inflorescences axillary panicles-fruits glabrous, greenish to white