1. Radical radicles: Flowers, fruits, & seeds

2. Flower development Plant must be mature Environmental triggers
activate floral genes
Growth bud becomes flower bud
Flower buds don’t elongate
Tissues differentiate

3. Flower structure Most flowers are “Perfect” Have male & female parts
(pistil = stigma + ovary)
Male parts
(stamen = anthers + filaments)
Male
Female
Most flowers are “Perfect”
Have male & female parts
Always monoecious
Some are “Imperfect”
Not always dioecious
Squash, corn, begonia

4. Flower structure: Composites
Sunflower – many small perfect flowers
Skunk cabbage & Anthurium – many small perfect flowers
Calla lily – females below, males above
(imperfect flowers)
Asters – “Florets”
Arums – “Spadices”

5. Pollination Required for seed development Pollen germinates,
Pollen tubes
Required for seed development
Pollen germinates,
fertilizes ovule(s)
Ovule(s) becomes seed(s)
Preventing self-pollination
Location, timing, sexual incompatibility…
Some do self-pollinate

6. Pollination Strategies
Wind, insect, animal
Nectar as an attractant
Flowers look different in UV
Some pollen glows!

7. Pollination Strategies
Sphinx moths
Star orchid
Darwin predicted this moth’s
existence 40 years before it was discovered in Madagascar!
Oregon wild ginger

8. Pollenation Strategies
Sphinx moths
Star orchid
Darwin predicted this moth’s
existence 40 years before it was discovered in Madagascar!
Oregon wild ginger

9. Seed Development After pollination, petals drop
Ovule matures to final form
(fruit, pod, capsule, etc.)
Cell division
Cell expansion
Starch accumulation
Ripening or hardening

10. Seed Dispersal Strategies
“Samara”
Seeds
Always come from flowers
No pollination, no seeds!
Many dispersal strategies
Fruits
Designed to be eaten
Sweeten when seeds mature
Seeds dispersed by animals

11. Kinds of Fruits (botanically)
Berries: multiple seeds from a single ovary in a single flower.
Grape, tomato, squash, papaya, cucumber, eggplant, banana, peppers, citrus, blueberry
Aggregates: multiple seeds from multiple ovaries in a single flower.
Blackberry, raspberry, strawberry
Drupes: single seed from a single ovary in a single flower.
Plum, cherry, peach, olive, apricot, mango, coffee, almond, pistachio, walnut, pecan
Pomes: from the Malinae subgroup of the Rose family.
Apple, pear, quince, loquat
Multiples: from several flowers that fuse into one fruit.
Pineapple, fig, mulberry, breadfruit, jackfruit
Nuts: from hardened ovary wall, seed within usually unattached.
Filbert, acorn, chestnut, beechnut
Legumes: from a single ovary in a single flower, forming a pod.
Beans, peas, lentils, carob, peanut, tamarind, alfalfa

12. Conifers & Cones Cones develop from female flower
Forgotten seed cache
Cones develop from female flower
Seeds borne under bracts
Have single wing
Some cones are “serotinous” and open only after fire

13. Seed Germination Environmental triggers
Epigeal germination
Hypogeal germination
Environmental triggers
Temperature, moisture, sunlight
Scarification: physical or chemical
Stratification: temperature
Radicle is first root
Cotyledons are first leaves
Endosperm is energy reserve
until leaves developed

14. Questions?