Page 44 - Pharmacognosy-I (02-06-06-102)

Form of Calyx:
The gamosepalous calyx is described as:
a. Tubular: having nearly parallel sides.
b. Campanulate: or bell-shaped.
c. Bilabiate: when irregular and bilipped.
d. Globose: when spherical in shape.
Structure of Sepals:
The sepals closely resemble leaf in structure but the mesophyll is
usually homogeneous.

Corolla

The corolla is the inner whorl of the non-essential floral-
leaves. Its main function is to attract the pollen carrying insects and
also to protect the essential organs of the flowers.

The corolla consists of two to five or more petals arranged in
a coloured modified leaves. The colour may be due to
anthocyanins dissolved in the cell-sap giving different colour
according to the change of pH (red, blue or violet). The colour may
be also due to flavonoids which are responsible for the yellow
colour or due to carotin and xanthophyll which are responsible for
the orange or red colour. The white colour is due to the reflection of
light from the intercellular spaces, but no pigments present.
Cohesion of petals:
1- Polypetalous: when the petals are free.

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