Stamen

2. Stigma Carpel Stamen Anther Style Filament Ovary Petal Sepal Ovule

3. Sepals Petals Stamens Carpels A B C C gene activity (a) A schematic diagram of the ABC hypothesis B  C gene activity Carpel A  B gene activity Petal Stamen A gene activity Sepal Active genes: B B B B B B B B A A A A A A A A A B A B B A A A C C C C A A B A C C C C C C C C C C C C Whorls: Carpel Stamen Petal Sepal Mutant lacking A Wild type Mutant lacking B Mutant lacking C (b) Side view of flowers with organ identity mutations

4. Microsporangium Carpel Anther Microsporocytes (2n) Mature flower on sporophyte plant (2n) Microspore (n) MEIOSIS Ovule with megasporangium (2n) Generative cell Tube cell Male gametophyte (in pollen grain) (n) Pollen grains Ovary Germinating seed MEIOSIS Stigma Pollen tube Megasporangium (2n) Sperm Embryo (2n) Surviving megaspore (n) Tube nucleus Endosperm (3n) Seed Seed coat (2n) Integuments Style Antipodal cells Female gametophyte (embryo sac) Polar nuclei in central cell Pollen tube Synergids Zygote (2n) Egg (n) Sperm (n) Nucleus of developing endosperm (3n) Egg nucleus (n) FERTILIZATION Key Haploid (n) Diploid (2n) Discharged sperm nuclei (n)

5. Abiotic pollination by wind Pollination by insects Common dandelion under ultraviolet light Common dandelion under normal light Hazel staminate flower (stamens only) Hazel carpellate flower (carpels only)

6. Pollination by bats or birds Long-nosed bat feeding on cactus flower at night Hummingbird drinking nectar of columbine flower

7. Pollen grain Endosperm nucleus (3n) (two polar nuclei plus sperm) Stigma Pollen tube Ovule Two sperm Polar nuclei Tube nucleus Style Egg Ovary Synergid Polar nuclei Zygote (2n) (egg plus sperm) Ovule Two sperm Egg Micropyle

8. Ovule Endosperm nucleus Zygote Integuments Zygote Terminal cell Basal cell Proembryo Suspensor Basal cell Cotyledons Shoot apex Root apex Seed coat Suspensor Endosperm

9. Seed coat Epicotyl Hypocotyl Radicle Cotyledons (a) Common garden bean, a eudicot with thick cotyledons Seed coat Endosperm Cotyledons Epicotyl Hypocotyl Radicle (b) Castor bean, a eudicot with thin cotyledons Scutellum (cotyledon) Pericarp fused with seed coat Endosperm Coleoptile Epicotyl Hypocotyl Coleorhiza Radicle (c) Maize, a monocot

10. Foliage leaves Cotyledon Epicotyl Hypocotyl Cotyledon Cotyledon Hypocotyl Hypocotyl Radicle Seed coat (a) Common garden bean Foliage leaves Coleoptile Coleoptile Radicle (b) Maize

11. Stigma Style Petal Flower Stamen Carpels Ovary Stamen Stamen Sepal Ovary (in receptacle) Stigma Ovule Ovule Apple flower Raspberry flower Pineapple inflorescence Pea flower Each segment develops from the carpel of one flower Remains of stamens and styles Carpel (fruitlet) Stigma Sepals Seed Ovary Stamen Seed Receptacle Raspberry fruit Pea fruit Pineapple fruit Apple fruit (c) Multiple fruit (a) Simple fruit (b) Aggregate fruit (d) Accessory fruit

12. Dispersal by water Coconut seed embryo, endosperm, and endocarp inside buoyant husk Dispersal by wind Giant seed of the tropical Asian climbing gourd Alsomitra macrocarpa Dandelion fruit Dandelion “seeds” (actually one-seeded fruits) Tumbleweed Winged fruit of a maple

13. Dispersal by animals Fruit of puncture vine (Tribulus terrestris) Squirrel hoarding seeds or fruits underground Ant carrying seed with attached “food body” Seeds dispersed in black bear feces

14. (a) Staminate flowers (left) and carpellate flowers (right) of a dioecious species Stamens Styles Styles Stamens Pin flower Thrum flower (b) Thrum and pin flowers

15. Asexual reproduction in aspen trees

16. (a) (b) (c) Developing root Laboratory cloning of a garlic plant