Question

Twisted aestivation is found in
a) Malvaceae
b) Asteraceae
c) Fabaceae
d) Mimosoideae

Answer 1

Hint: Aestivation is defined as the mode of arrangement of sepals and petals in flower with respect to the members of the same whorl.

Complete answer:
> Malvaceae has flowers like Hibiscus, Malva, etc. the corolla is polypetalous showing twisted aestivation.

> Asteraceae is the sunflower family. They usually have flowers that are pentamerous and epigynous. The corolla is gamopetalous showing valvate aestivation.

> Fabaceae includes legumes like a garden pea. The flower is gamosepalous and polypetalous showing imbricate aestivation.

> Mimosoideae- The best example is the Mimosa plant. The corolla can be gamopetalous or polypetalous showing valvate aestivation.

Thus the correct answer is option A- Malvaceae.

Additional information:
There are four types of aestivation- Valvate, twisted, Imbricate, and Vexillary as shown below:

1. Valvate- The aestivation is said to be valvate when the margins of sepals or carpels remain either in contact or lie close to each other but do not overlap. Example- Datura.

2. Imbricate- In this type, one of the sepals or petals is internal, overlapped at both margins and other is external, overlapping margins of other sepals or petals. Example- Cassia.

3. Twisted- In this type, one margin of each petal or sepal is internal while the other is directed outwards and overlaps the margin of the adjacent one. Example- Hibiscus.

4. Vexillary- In this corolla is butterfly-shaped consists of five petals. Among these, the outermost is largest and is called standard or vexillum, two lateral petals are known as wings and two smaller nearly fused petals forming boat-shaped structure called keel or carina. The vexillum overlaps wings that overlap the keel. Example- Pea.

Note: Flowers of different families have different numbers of petals or sepals and thus show different types of aestivation.