What is heterospory? Briefly comment on its significance. Give two examples.

Explanation

Genera like selaginella and salvinia in Pteridophytes bear two kinds of spores macro ( large ) and micro ( small ) spores are called heterosporous . Microspores and megaspores germinate to give rise to male and female gametophytes respectively.
Significance . The female gametophytes in heterosporous plants are retained on the parent sporophytes for variable periods . The development of zygotes into young embryos occur in female gametophytes . This step is said to be precursor of seed habit in gymnosperms and angiosperms where all the members are heterosporous.