Question

Which of the following are homosporous?
A. Salvinia, Equisetum
B. Salvinia, Lycopodium
C. Selaginella, Salvinia
D. Lycopodium, Equisetum

Answer 1

Homosporous plants are the ones that produce spores that are identical to each other and can not be differentiated morphologically or anatomically. This is generally observed in all Bryophytes and most of the Pteridophytes.

Complete answer:
Plants can be differentiated into two types based on the spores produced by them- Homosporous and Heterosporous. Heterosporous plants are the ones that produce spores that are non-identical to each other and have different morphology. These spores are easily distinguishable as they differ in their shape and size. These spores are unisexual and are differentiated into male and female gametes that develop into male and female gametophytes.
Homosporous plants are the ones that produce spores that are exactly similar to each other in shape and size and cannot be distinguished from each other. These spores are bisexual and thus consist of both male and female gametes. They later develop into bisexual gametophytes. These gametophytes have separate sex organs for the production of male and female gametes. Homospory is mostly observed in all Bryophytes and most of the Pteridophytes or lower vascular plants. These plants have a special mechanism that prevents the fusion of male and female gametes in the bisexual gametophyte.

Let us analyze the options to find the correct answer.

Option A: Salvinia and Equisetum, the former here show heterospory in the formation of the spores while the latter shows homospory. Since one of them shows heterospory, therefore, this is an incorrect option.
Option B: Salvinia and Lycopodium, the former here show heterospory in the formation of the spores while the latter shows homospory. Since one of them shows heterospory, therefore, this is an incorrect option.
Option C: Selaginella and Salvinia are both heterosporous plants. Therefore, this is an incorrect option.
Option D: Lycopodium and Equisetum are both homosporous pteridophytes plants. Therefore, this is the correct option.

Hence, the correct answer is option (D)

Note: The pteridophytes that show homospory are Psilotum, Tmesiptris, Lycopodium, Equisetum, Phylloglossum etc. Mostly non-flowering plants are homosporous. There is no differentiation of megaspore and microspore in these plants.