Question

What are the different shapes corolla can have?

Answer 1

Hint: There are four axillary whorls in the plant which are calyx, corolla, gynoecium, androecium. The corolla is the second axillary whorl. Calyx consists of sepals and corolla contains petals. The gynoecium and androecium have the female and male reproductive parts respectively.

Complete answer:
The colours of the petals, fragrance of essential oils and the secretion of the nectar by some special glands are the properties that make a flower highly attractive to pollinators like insects. Sometimes these petals can be of green colours or have some dull colours, the same as sepals. These types of petals are known as sepaloids. Petals can be of different shapes like linear, oval, round etc. The petals can be regular or irregular. They may have some appendages like in Antirrhinum, the Corolla tube is slightly dilated which forms a pouch-like structure which stores nectar. This type of flower is known as spurred.
The different forms of corolla are mentioned below-
A) Polypetalous - In cruciforms, the four petals are free clawed and are arranged like a cross (mustard). Five petals are free clawed with their limbs perpendicular to the claws seen in Dianthus. Five very short claws with their limbs spreading outwards are seen in the rosaceae family. Five free petals in butterfly shape are present in the papilionaceous family.
B) Gamopetalous - Corolla tube of sunflower is cylindrical and the limbs are supposed to be not spreading (tubular). The tube is rounded at the base side while it widens up as it goes upwards (bell shaped). Eg- cucurbits. In datura, the corolla is like a funnel shaped structure. The coral is salver shaped in Vinca rosea. Wheel-shaped in Solanum melongena, lingulated in the composite family, masked in the Snapdragon.

Note:
The arrangement of petals is known as aestivation. It can be of several types like valvate, imbricate, twisted or vexillary. In valve aestivation, the petals are connected end to end but are not overlapped. In twisted form, the petals are overlapping each other in a definite pattern. In imbricate form, the overlapping is not in a specific pattern. In vexillary form, there is a standard petal, two wings and one keel.