1. Flowers & Flowering

2. Why flowers? location for sexual reproduction in Angiosperms
co-evolved with the pollinators
symbiotic relationship – all species involved benefit!

3. Flower Anatomy Many sizes, shapes and colors
Most contain the following organs in some shape or form
Petals
Sepals
Stamens
Pistols

4. Petals Usually brightly colored
Often have perfume or nectar at the base
Provide surface for pollinators to rest on as they feed
All of the petals together are called the corolla

5. Sepals
Usually found in a ring at the base or outermost portion of the flower
Serve as protective covering for the flower bud
All of the sepals together are called the calyx

6. Stamen – male reproductive structure
Made up of the anther and filament
The anther is found at the tip of the filament – this is where pollen is produced
The number of stamens varies from flower to flower

7. Pistil/Carpel – female reproductive structure
Made up of the Stigma, Style and Ovary
The stigma is at the top of the pistil. It’s role is to receive the pollen
The style connects the stigma to the ovary
The ovary is at the base. It contains ovules that produce eggs
The number of ovaries varies in flowers

9. Complete vs Incomplete Flowers Perfect vs Imperfect Flower
Complete flowers: pistils, stamens, sepals and petals
Incomplete flower: lacking any of the parts
Perfect flower: has both pistils and stamens
Imperfect flower: lacks either pistils or stamens

10. Monoecious vs Dioecious
Monoecious –separate male and female flowers on the same plant
Ex. Corn, pecans, walnuts, cucumbers, and squash
Dioecious – separate male and female plants
Ex. Holly, ginkgo, pistachio, and marijuana

11. Photoperiodism
Photoperiodism: response of flowering plants to daily daylight-darkness conditions
Ensures all plants of the same species bloom at the same time

12. Critical Period
The specific daylight-darkness conditions that will make flowering begin
Day length is not what matters – amount of darkness is what matters
The names are misleading – the categories were named before scientists realized it was darkness, not light, that prompted flowering

13. 4 Categories
Short-day: daylight is shorter than critical period – asters, poinsettias, strawberries
Long-day: daylight is longer than critical period – carnations, petunias, potatoes
Day neutral – flowers over a range of daylight hours, day length is not what induces flowering
Intermediate day – will not flower if days are longer or shorter than critical period – sugarcane and grass