Studies on reproductive biology of a threatened tree fern, Cyathea spinulosa Wall. ex Hook

Cyathea spinulosa Wall. ex Hook. is a highly-prized ornamental and economic tree fern and a significant component of tropical forests in southern, central and northern India. Currently, it is under threatened status and listed in the Red Data Books. Since the successful colonization of a fern in new habitats is dependent on gametophyte generation, the present study was conducted to observe the reproductive biology of the species. Sex ontogeny showed male gametophytes to hermaphrodite condition and the gametophytes remained bisexual for considerable period of time. Regeneration of gametophyte was common; the regenerated portions bore both sexes and produced sporophytes extensively. The reproductive behaviour revealed considerable success in sporophyte production through intragametophytic selfing. This shows that the species is of lesser genetic diversity and the gene pool is charged with lesser amount of genetic load, and is a good colonizer. In contrast, the taxon is under threatened status. The cause of this and the probable mode of conservation are also discussed here.