Question

Among flowers of Calotropis, Tulip, Sesbania, asparagus, Tobacco and Groundnut, how many plants have valvate aestivation?
A. Four
B. Eight
C. Five
D. Six

Answer 1

A flower has four whorls- calyx (group of sepals), corolla (group of petals), androecium and gynoecium. Aestivation is the mode of arrangement of sepals or petals in relation to one another in a flower bud is called aestivation.

Complete answer:
The various types of aestivations found in plants are:
Open- In this type, the petals of a whorl or sepals of a whorl are sufficiently apart from each other.
Valvate- In this, the petals of a whorl or sepals of a whorl meet by their edges but do not overlap. The valvate aestivation is further of three types- duplicate in which the margins are projected inwards, reduplicate in which the margins are projected outwards and involute in which the margins are rolled inwards. It is found in flowers of Tulip, Calotropis, Sesbania, and asparagus.
Twisted or contorted- In this, the margins of petals are overlapping regularly i.e. one margin of a petal overlaps the next and the other margin is overlapped by preceding petal. Twisting may either be clockwise or anticlockwise.
Imbricate- The margins of petals in this are overlapping irregularly. Out of five petals, one is completely internal, one is completely external and in each of the three remaining petals one margin is internal and the other is external.
Ascending imbricate- It is a type of imbricate aestivation in which the posterior petal is internal.
Descending imbricate or Vexillary- It is a type of imbricate aestivation with internal anterior petal. The posterior petal is largest and it almost covers the two lateral petals and the later in their turn nearby overlap the two anterior and the smallest petals.
Quincuncial- It is the modification of imbricate aestivation in which the two petals are internal. Two are external and the fifth one has one margin external and other margin internal.
So, the correct answer is “Option C”.

Note: The whorls of sepals and petals are called calyx and corolla respectively. The sepals are essentially green and protect the other parts of the flower in bud condition but the petals are generally colored, showy, attractive and fragrant.