1. School of Sciences, Lautoka Campus BIO509 Botany Lecture 21: Angiosperms
Photo courtesy of Prof. Randy Thaman

2. Flowers , Fruits and seeds

3. Learning Outcomes
Know the parts of a flower and the function of each part.
Understand the differences between monocot and dicotyledonous plants.
Know the different types of fruits.
Learn the adaptations of fruits and seeds that aid in dispersal.

4. Flowers Flowering plants are essential for animals and humanity.
Provide countless products.
80% of world’s food resources.
Flowering plant habitats are varied as their forms.

5. Flowering plant types
Annuals – life cycle is completed in a single season, parent plant dies.
Biennials – life cycle is completed in two growing seasons.
Perennials – life cycle is completed over several growing seasons.

6. Two major classes Monocots Dicots
More than ¼ of angiosperm species are monocots (~70,000 sp.)
More than ⅔ of angiosperm species are eudicots (~170,000 sp.)

7. All flowers share the basic features

8. Inflorescences
Groups of several to hundreds of flowers that may open at the same time

9. Seed and fruit formation
After fertilization
Seeds develop from the ovules.
Fruits develop from the ovary.

10. Fruit Matured ovary and its accessory parts.
However, it may have other bits fused to it
(E.g. hypanthium, calyx, etc).
Some form by apomixis (seed formation without sexual fusion).

11. What is the function of fruits?

12. Mature fruit had three major regions
Ovary wall (known as pericarp in the fruit) often thickens and develops into 3 layers
Exocarp – outer layer
Mesocarp – middle layer
Endocarp – inner layer

14. Classification is based on these features.
Fruits may be fleshy or dry at maturity.
May or may not split to expose the seeds.
May be derived from a single ovary or from multiple ovaries.
Classification is based on these features.

15. Different kinds of fruits

16. Fleshy fruits Mesocarp is partly fleshy at maturity.
Simple fleshy fruits – formed from a flower with single carpel (ovary), superior or inferior ovary.
Fruit types include:
- Drupe
- Berry
- Pepo
- Hesperidium
- Pome

17. Drupe
Simple fleshy fruit with one seed enclosed by a hard stony endocarp or pit.
Usually superior ovary.
Mesocarp not always obviously fleshy (e.g. coconut).
E.g. cherry, peach, plum, olive, almond, coconut

18. Berries
Thin-skinned simple fleshy fruit with mesocarp and endocarp difficult to distinguish from each other
Derived from superior, compound ovary
Most more than one seed
Avocados and dates one-seeded
E.g., grapes, peppers, egg-plant, tomato, papaya, guava.

19. Pepo Berry with a relative thick rind
Restricted to members of the pumpkin family (Cucurbitaceae)
E.g. squash, cucumber, pumpkin, gourd, watermelon, cantaloupe

20. Hesperidium Berry with a leathery skin containing oils.
Restricted to and characteristic of the citrus family (Rutaceae).

21. Accessory fruit with thick hypanthium.
Pomes
Accessory fruit with thick hypanthium.
Bulk of flesh comes from enlarged floral tube or receptacle that grows up around the ovary. E.g Apples and pears.

22. Compound Fleshy Fruits - derived from several ovaries or flowers.
Fruit types include:
Aggregate fruit
Multiple fruit
Synconium (multiple fruit)

23. Aggregate fruit Develop from a single flower with numerous pistils.
Pistils mature as a clustered unit on a single receptacle
E.g. Raspberries, Strawberries.

24. Multiple fruits
Develop from many individual flowers in a single inflorescence.
E.g. Pineapples, figs, maize, noni (kura), pineapple, breadfruit, mulberry.

25. Multiple fruits

26. Syconium
A type of multiple fruit in which the receptacle entirely encloses the inflorescence.
Characteristic of figs (genus Ficus).
Pollinated by tiny wasps that enter the tiny opening at the top.

27. Individual flowers

28. 1 2
Fig Pollination 3 4

29. Dry Fruits Fruits with a dry pericarp
Dehiscent fruits
Split open at maturity, seed fused to pericarp.
Fruit types include:
Follicles , Legumes, Siliques, Capsules.

30. Follicle
Formed from single carpel & splits open down one side to release the seeds.
Splits open along a seam.
E.g., milkweed, magnolia, banksia, monk’s hood.

31. Legume (pod) Splits along two seams.
Formed from single carpel with seeds in one row.
Mostly in legumes (Fabaceae = Leguminosae).
E.g. Peas, beans.
Peanuts unusual: do not split on their own

32. Silique
Splits along two seams, with seeds borne on a central partition.
Originates from 2 carpels.
Characteristic of mustard family (Brassicaceae).
E.g., mustard, watercress, cabbage, raddish.

33. Capsule
Formed from a compound ovary, splits open along multiple seams or forms pores.
May open along seams, between seams, or by pores.
E.g. poppy, cotton, orchids, lilies.

34. Indehiscent fruits
Do not split open at maturity, seed fused to pericarp.
Fruit types include:
Achene
Nut
Caryopsis
Samara
Schizocarp

35. Achene only the base of seed is fused to pericarp.
Seed is easily separated from ovary wall.
All of Asteraceae, e.g. sunflower seeds
The real fruits of the strawberry are also achene but are fleshy fruits.

36. Nut Like achene, but larger and pericarp harder & thicker.
Single seed with hard pericarp/husk
Develops with a cluster of bracts at base.
Acorns, hazelnuts, hickory nuts, walnut.

37. Many fruits called nuts in English are not actually nuts.
E.g., peanuts, coconut, Brazil nuts almonds, cashews

38. Caryopsis (grain)
Indehiscent fruit with the pericarp tightly united with the seed and inseparable.
One-seeded fruit/seed fused with seed coat (pericarp)
All members of the grass family (Poaceae)

39. Samara Pericarp extends out to form a wing or membrane.
One wing common, but sometimes more.
Aids in dispersal.
E.g., maple, ash

40. Schizocarp
Comprises two or more segments (mericarps) that separate from each other.
Split apart at maturity.
Whole seed separates to form 2 separate 1-seeded fruitlets
Apiaceae (carrot family) species: twin fruits (more in other families)

41. Questions??