Question

When stamens are fused by their anthers and the filaments are free, the condition is called
a. Monadelphous
b. Synandrous
c. Syngenesious
d. Epipetalous

Answer 1

Hint: The condition is observed in Sunflower. The stamen is referred to as the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium.

Complete answer:
- The third whorl of the flower is the male reproductive part of the flower. It is composed of stamens(microsporophylls).

- A stamen typically consists of a stalk called the filament and anther which contains microsporangia. The two-lobes of anthers are attached to the filament either at the base or in the middle area of the anther.

- Depending on the species of plant, some or all of the stamens in a flower may be attached to the petals or the floral axis. They may be free-standing or fused in many different ways, which includes a fusion of some but not all the stamens. The filaments may be fused and the anthers free, or the filaments free and the anthers fused.

- The androecium of flowers shows varying cohesion that is union among the stamens themselves and adhesion, that is union with other floral parts.

- Cohesion refers to the fusion of stamens among themselves. It is of 3 types. Adelphy, Syngenecious, Synandrous.

- Monadelphous condition refers to the filaments that are united to form a single bundle while anthers are free. Synandrous refers to the stamens are united in their whole length. Epipetalous refers to the condition where stamens are fused with petals.

- The androecium of syngenesious is a feature of the family Asteraceae where the anthers are fused but the filaments are free.

- It is a condition about an aggregate of stamens fused at the anthers. There are usually five stamens.

- The filaments are fused to the corolla, while the anthers are generally connate thus forming a sort of tube around the theca(style). They commonly have apical appendages.

Hence, the correct option is (C), Syngenesious is the condition where the stamens are fused by their anthers and filaments are free.

Note: The androecium in various species of plants forms a great variety of patterns, some of them are highly complex. The number of stamens differs in different plants and the fusion is also different according to the plant species.