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Flowers


Flowers are a group of highly specialized structures used in the sexual reproduction of angiosperms. Every aspect of a flower (appearance, scent, pollen, nectar, etc.) is adapted for efficient pollination to produce seeds.

Flower types according to ovary position and fusion of flower parts:

Superior ovary:

Perianth and stamens attach to receptacle below the ovary

Hypogynous flowers:

One or more pistils, each with a superior ovary;
the bases of the perianth and stamens are separated.

Examples: geranium, carnation.

Perigynous flowers

One or more pistils, each with a superior ovary;
the bases of the perianth and stamens are fused into a cup-like hypanthium.

Example: rose.

Inferior ovary:

Perianth and stamens join on top of the ovary

Epigynous flowwers

A single pistil with an inferior ovary;
perianth and stamens can also fuse with ovary to form hypanthium.

Examples: orchid, apple, fuschia, squash.


Flower types according to sexual variations:


Although the basic structure of a flower has four floral series, specialized variations have evolved for greater efficiency.
PERFECT
bisexual or hermaphrodite

Has both fertile floral series.
COMPLETE
always perfect
Has all four floral series.
Examples: hibiscus, cactus, tulip.
INCOMPLETE A perfect flower missing one or more sterile floral series.
IMPERFECT
unisexaul

Has only one fertile floral series.
always
INCOMPLETE
Pistillate flowers: with only gynoecium
Staminate flowers: with only androecium


Plant types:

Flowering plants are categorized according to their flower types.

Monoclinous

Plants with perfect flowers

Diclinous


Plants with imperfect flowers

Monoecious

Have both male and female flowers on the same plants.
Common with wind-pollinated plants.
Examples: maize, amorphophallus, jackfruit etc..

Dioecious

Male and female flowers on separate plants.
No self-pollination (leading to greater diversity), but requires plants with opposite sexes to be close together.
Examples: tropical pitcher plant, sweet bay, ginkgo, date palm, holly, asparagus, pampas grass etc..

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