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
Perianth
When the two whorls- calyx and corolla are not clearly differentiated
Tepal
Individual member of perianth
Monadelphous
Stamens are united into one group by their filaments only but the anthers remain free/
E.g. Hibiscus (*underline)
Diadelphous
The filaments are united into two bundles but the anthers remain free.
E.g. Pisum (pea) (*underline) where nine filaments form one bundle and the tenth stands apart
Polyadelphous
Filaments are united into several groups, the anthers remain free
E.g. Bombax (*underline)
Epipetalous
Stamens adhering to the corolla by their filaments
E.g. brinjal
Dithecous anther
Two lobed anther
E.g. Citrus (*underline)
Monothecous
One lobed anther e.g. Hibiscus (*underline)
Basifixed
Filament attached to the base of the anther
E.g. Brassica (*underline)
Dorsifixed
Filament attached to the back of the anther
E.g. Hibiscus (*underline)
Unilocular
Ovary with one chamber
E.g. Stellaria (*underline)
Bilocular
Ovary with two chambers
E.g. Solanum (*underline)
Trilocular
Ovary with three chambers
E.g. Asphodelus (*underline)
Tetralocular
Ovary with four chambers
E.g. Ocimum (*underline)
Multilocular
Ovary with many chambers
E.g. Citrus (*underline)
Placentation- Definition
The arrangement of ovules within the ovary is known as placentation
Marginal placentation
Ovules are borne along the ventral suture of the carpel
E.g. Pea
Axile placentation
Ovules are borne on the central axis
E.g. Citrus
Parietal placentation
Ovules are borne on the margin
E.g. Brassica (*underline), custard apple
Basal placentation
The ovary is unilocular and the solitary ovule appears to arise from the base of the ovary
E.g. Mango, Dates
Inflorescence
Mode of arrangement of more than one flower on a single stalk
Racemose inflorescence
The floral axis shows indeterminate growth producing flowers in an acropetal order i.e. the older flower is the lowest and the youngest uppermost
E.g. cherry
Cymose inflorescence
In a cymose inflorescence, the main axis has limited growth and the flowers are arranged in a basipetal manner i.e. the older flowers are found towards the top and the younger ones towards the base of the axis.
E.g. Ocimum (*underline)
Fruit- definition
Mature or ripened ovary
Parthenocarpic fruits
Fruits that are formed without the act of fertilization
Syngenesious
Anthers are united to form a cylinder around the style, filaments remain free
E.g. sunflower
