Identify the pair of heterosporous pteridophytes among the...

Pteridophytes are the true land plants and show the following salient features:

1. They have predominant sporophytic generation and diploid nature.
2. The gametophyte is independent, called prothallus in ferns.
3. They have evolved vascular tissue for conduction of water and minerals.
4. Some genera, like Selaginella, Salvinia, Isoetes, Azolla, etc. produced two types of spores, microspores and megaspores. This is called heterospory. This gave birth to seed habit.