Question

Microsporophyll of Selaginella is the forerunner of which structure of angiosperm
A. Pollen sac
B. Microsporangium
C. Stamen
D. Carpet

Answer 1

Hint: Selaginella is a heterosporous plant and produces two types of spores. The microspores are produced inside the microsporangia from the microspore mother cells. The microsporangia in Selaginella are borne on microsporophyll while that of the angiosperms are present in the anthers of the stamen. Therefore, serves as the forerunner of the stamens of the flowering plants.

Complete answer:
Stamens of the flowering plants are composed of filament and anther. The filament is a thin stalk-like structure that bears the anther at its top. The anther is the part of the stamen where the microspore mother cells present in the microsporangia/pollen sacs undergo meiosis to produce the microspores of pollen grains. Each pollen grain servers as the male gametophyte and produces two cells one of which eventually produces two male gametes.

Now, if we talk about the Selaginella, one should know that Selaginella is an example of heterosporous ferns and produces microspores and megaspores in the microsporangia and megasporangia. The microspore mother cells present inside the microsporangia undergo the process of meiosis and produce haploid microspores. Each of these microspores gives rise to the male gametophyte.

The microsporangia of the Selaginella are borne on the microsporophylls which are present in the spiral fashion and form compact cones or strobili. Since the microsporangia of the angiosperms are present in the anther of the stamen, the microsporophyll of Selaginella is the forerunner of the stamen of the angiosperms.

Hence, The correct answer is option (C).

Note: Microsporangia and pollen sac are used synonymously. Heterospory in plants like Selaginella served as a forerunner for the evolution of seeds as produced by the two most successful groups of the plants present on the earth: gymnosperms and angiosperms. One should know that angiosperms are also called flowering plants while gymnosperms do not produce flowers. However, both produce seeds.