Genera like Selaginella and Salvinia produce two kinds of spores. Such plants are known as :

The correct option is Heterosporous.

To understand why plants like Selaginella and Salvinia are described as heterosporous, let us break down the botanical concepts:
1. Definition of Spores: Spores are the microscopic reproductive units of non-seeded vascular plants (like pteridophytes) that germinate to form the gametophyte generation.
2. Homosporous vs. Heterosporous:
- Homosporous plants: The prefix "homo-" means "same". These plants produce only one type of spore. These spores are identical in size and shape and grow into bisexual gametophytes. Most ferns and clubmosses are homosporous.
- Heterosporous plants: The prefix "hetero-" means "different". These plants produce two distinct kinds of spores that differ significantly in size and function: microspores (smaller spores) and megaspores (larger spores).
3. Microspores and Megaspores:
- Microspores: These are smaller in size and germinate to produce the male gametophyte, which subsequently produces male gametes (sperms).
- Megaspores: These are larger in size and germinate to produce the female gametophyte, which bears the female reproductive organs and produces female gametes (eggs).
4. Evolutionary Significance: Genera like Selaginella (spike mosses) and Salvinia (aquatic ferns) are prominent examples of heterosporous pteridophytes. Heterospory is considered a key evolutionary precursor to the seed habit found in higher plants (gymnosperms and angiosperms), as it allows for the differentiation of male and female gametophytes and internal fertilization.

Therefore, plants that produce two kinds of spores are termed heterosporous.