Morphology of Flowering Plants Flashcards
Phyllotaxy
Phyllotaxy is the mode of arrangement or distribution of leaves on the stem and its branches
Complete flower
A flower having all four whorls- calyx, corolla, androecium, gynoecium is called a perfect or complete flower
Staminate flower
Unisexual flowers having only stamens
Pistillate flower
Unisexual flower having only carpels
Monoecious
Both staminate and pistillate flowers on the same plant
Dioecious
Staminate and pistillate flowers on different plants
Why is a hypogynous flower said to have a superior ovary? Give examples
Because the calyx, corolla, and stamens are inserted below the ovary
e.g. Brassica (mustard) (underline)
Hibiscus (underline)
What is a perigynous flower? Give e.g.
The thalamus forms a cup shaped structure around the ovary and the sepals, petals and stamens appear to be inserted on the rim of the cup.
The ovary is said to be semi-inferior
E.g. rose
Epigynous flower + e.g.
When the thalamus completely encloses the ovary and the sepals, petals and stamens appear to be arising from above the ovary, it is known as an epigynous flower
It has an inferior ovary
E.g. cucumber, guava, ray florets of sunflower
Actinomorphic
When a flower can be divided into two exactly equal halves in any plane it is said to be actinomorphic
E.g. Hibiscus, Brassica (*underline)
Zygomorphic
When a flower can be divided into two equal halves by a vertical section in one plane only
E.g. pea flower
Aestivation
Mode of arrangement of sepals/petals in a floral bud with respect to other members of the same whorl is said to be aestivation
Valvate aestivation
Memebers of a whorl are in contact with each other by their margins, without overlapping
E.g. Brassica, periwinkle
Twisted aestivation
One margin of a member covers the margin of the next member and the other is covered by the one before it
E.g. hibiscus
Imbricate aestivation
One member of the whorl is exterior, one is interior, and the rest three have one margin exterior and one interior.
E.g. Cassia (*underline)
Vexillary aestivation
Largest (standard) petal covers two lateral petals (wings) which overlap the smallest (keel) petal.
E.g. pea