Lab #6B

1. Lab #6B Angiosperms

2. Flowers Stigma Carpel Stamen Anther Style Filament Ovary • structure of a flower – 4 rings of modified leaves called flower organs: • 1. sepals • 2. petals • 3. stamens • 4. carpels Stigma Style Anther Filament Sepal Petal Sepal Ovule Receptacle

4. Perfect flowers • male and female on same plant • lilies • dandelions • roses • virtually every fruit and vegetable plant in North America • tomatoes dandelion african violet apple blossom

5. Imperfect flowers • male and female reproductive parts on separate flowers • but may be on the same plant • staminate flowers • carpellate flowers staminate flowers

6. Inflorescences • inflorescences = group of cluster of flowers arranged on a stem that is comprised of a main branch or a complicated arrangement of branches • several types • raceme - unbranched main axis, flowers attached by a pedicel • spike – unbranched main axis, directly attached flowers • panicle – branched main axis • corymb • head (flower head) – also known as a composite flower

7. Composite flowers • composite flowers = clusters of many small flowers called florets – each of which is a full flower • chicory, dandelion, chrysanthemum, yarrow, coreopsis, sunflower, dahlia, zinnia, goldenrod, aster, lettuce, thistle and Black-eyed Susan. • composites are miniaturized flowers • numerous flowers packed onto a platform called a receptacle, • so the sunflower is actually a collection of hundreds of flowers! • two kindsof flowers: disk flowers and ray flowers • disc flowers – center of the receptacle • ray flowers – surround the disc flowers (look like petals) disc flowers ray flowers

8. Flower ovules Lilium ovary with ovules Ovary with ovule Ovary with ovules

9. Ovules Ovule Ovules

10. Anthers

11. Fruit • composed of an outer wall = pericarp and the inner placenta with seeds • pericarp is made up of an exocarp, a mesocarp and an endocarp • e.g. apple – skin = exocarp; flesh = mesocarp; paper part in the center = endocarp; seeds • classified as: simple, multiple or aggregate • simple – one carpel or several fused carpels form the fruit • e.g apple • multiple – more than one flower with female parts • aggregate – number of separate carpels form the fruit

12. Fruits – dichotomous tree • first division – fleshy or dry • I. Fleshy • A. simple (from a single ovary) or B. complex (from more than one ovary) • A. simple- drupe (hard endocarp = cherry, olive, coconut), berry (fleshy endocarp = tomato, grape, peppers, cucumbers), pome (apples, pears) • B. complex – aggregate (fruit from many carpels on a single flower = strawberry, raspberry), multiple (fruit from carpels of many flowers fused together = pineapple, corn) • II. Dry • A. fruits that split open at maturity (more than one seed) or B. fruits that do not split (one seed) • A. fruits that split – along one seam (peas, beans and peanuts), along multiple seams (okra, lilies, poppies) • B. fruits that don’t split – hard pericarp (acorns, chestnut), thin pericarp and winged (maples, ash, elm), thin pericarp no wings (sunflowers, cereal grains, grasses)

13. Placentation • ovules develop from the placenta and are attached to the ovary wall until maturation into seeds • arrangement of the placenta = placentation • parietal – ovules on the outer ovary wall or extensions of it • free central – ovules along a central column or axis • axile – ovules along a central axis which is connected to the ovary wall

14. Placentation Parietal placentation Axile placentation