$Selaginella$ and $Salvinia$ considered to represent a significant step towards evolution of seed habit because

Which feature distinguishes the prothallus of Psilotum from that of most other pteridophytes?

Consider the following statement regarding heterospory

I. Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous

II. The megaspores and microspores germinate and give rise to female and male gametophyte respectively

III. The female gametophytes in these plants are retained on the parent sporophytes for variable periods

IV. The development of the zygotes into young embryos takes place within the female gametophytes

V. This event is a precursor to the seed habit considered an important step in evolution

The dominant generation in the life cycle of a Pteridophyte is the:

In which plant group is the retention of the female gametophyte with the developing embryo on the parent sporophyte first observed as a significant evolutionary step?

Which of the following pteridophytes is heterosporous?

Pteridophytes differ from bryophytes in the

Which of the following is a characteristic feature of Selaginella and Salvinia related to spore production?

Ectophloic siphonostele is found in

Which one of the following is called maiden-hair fern?

Which of the following pteridophytes is heterosporous