Question

Odd sepal is enlarged and leaf-like in
A. Rose
B. Smilax
C. Mussaenda
D. Bougainvillea

Answer 1

Hint: The sepal is a part of leaf-shaped structure that is found in the outermost whorl of a flower of angiosperms (flowering plants). Usually, the sepal is in green colour and typically ensures the function of protecting the flower from different kinds of insects when it is in bud condition.

Complete answer:
Though sepals are usually green in colour and form a leaf like structures, there are some plants which have modifications in several forms for various purposes. Presence of only one leaf-like shaped structure is known as odd sepal.
-In Rose, the flower of most species has five sepals beneath the five petals except the species, Rosa sericea which usually contains only four sepals and four petals.
-The species of Smilax belongs to the family Smilacaceae. Here, the petals and sepals are undifferentiated and the flowers are made of 6 tepals.
-In Bougainvillea, the appearance of flowers is brightly coloured in which it has five sepals resembling the petals.
-Mussaenda species is a flowering plant of Rubiaceae family. They have an enlarged sepal in their flowers. In the calyx of Mussaenda, the sepal forms a leaf-like structure and has brightly coloured or white petaloid sepals in order to attract the insects for pollination. Resembling a leaf-like shape (Foliaceous shape) of sepals is found in Mussaenda.

Hence, the correct answer is option (C).

Note: In the calyx of Aconitum, one of the sepals is modified to form a hood like structure which covers the outermost whorl of the whole flower.
In the fruits of Trapa and Water chestnut, the sepals are modified into spines and help in the function of protecting the fruit.