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Evolution of Angiosperms. Archaefructus sinensis. Controversy over when this first appeared Best bet is 125 MYA No sepals or petals, just stamens and carpels. Stamens thought to have attracted pollinators. Phylum Anthophyta. Non Monocot Paleoherbs
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Evolution of Angiosperms Archaefructus sinensis Controversy over when this first appeared Best bet is 125 MYA No sepals or petals, just stamens and carpels. Stamens thought to have attracted pollinators
Phylum Anthophyta • Non Monocot Paleoherbs • Nymphales (water lilies), Aristolociales (pipe vine) • Magnoliids • Magnoliales (Magnolia) Laurales (Red Bay) • Monocotyledones (monocots) • Grasses, lilies, irises, orchids, cattails, palms • Eudicotyledons (eudicots) • most familiar trees and shrubs (other than conifers and palms) and many herbs
Helianthus annuus Sunflower Asteraceae- Composites Usually: inferior ovary, stamens 5 fused, petals 5 fused, sepals absent/reduced Small disk flowers clustered together Ray flowers around periphery (carpellate or sterile)
Flowers • Angeion (vessel) + sperma (seed) = Angiosperm • Perfect flowers- bisexual, stamens and carpels • Imperfect flowers- unisexual, either staminate or carpellate • Monoecious species- both staminate and carpellate flowers on one plant (ex. oaks) • Dioecious species- staminate and carpellate flowers on separate individuals (ex. willows)
Locate: Stamens Filament Anthers Pistil Stigma Style Ovary • Pedicel • Receptacle • Calyx • Sepals • Corolla • Petals • Tepals
Clustered flowers -aggregated into different types of inflorescences
Superior ovary- (ex. lily) sepals, petals, and stamens are attached below the ovary Inferior ovary- sepals, petals and stamens attached near the top of the ovary Intermediate conditions:
Malus domestica Example of epigyny -sepals, petals, stamens apparently arise from the top of the ovary
Pollen grains -wall protects male gametophyte -sculpturing of wall is distinctive and species specific -Lilium longiflorum
Placentation Parietal Axile Free-central
Fruits • Just as flowers evolve for pollination, fruit evolves for dispersal • Fruit is a mature ovary • Types • Simple: one (or united) carpels • Aggregate: many separate carpels from one ovary (magnolia, raspberry, strawberry) • Multiple fruits: ovaries of >1 flower (pineapple)
Dry, indehiscent • Achene- small, single seeded fruit (Ranunculaceae, Polygonaceae) • Samaras- winged achenes (elms, ashes) • Caryopsis- grain or achene-like fruit in grasses • Schizocarp- splits at maturity into 2+ one-seeded portions (Apiaceae)
Dry, dehiscent • Follicle- single carpel, splits down a side (columbines, milkweeds) • Legume- Fabaceae- like follicles but split down both sides • Silique- Brassicaceae Mustard family- 2 fused carpels, sides split off at maturity leaving seeds attached to the central portion • Capsule- compound ovary (superior or inferior) (poppies)
Fleshy Fruits • Berry- 1-many carpels, each often many-seeded, inner layer of wall fleshy (tomato, date, grape) • Drupes- 1-many carpels with only 1 seed each, inner layer of fruit stony (peach, cherry, olive) • Pomes- subfamily in Roseaceae- compound inferior ovary with large fleshy part from the base of the perianth- also an accessory fruit (apple, pear)
Modes of dispersal • Wind • Water • “Drop” dispersal • Mechanical • Animal (ant, insect, mammal): Internal and external