Mosses (bryophytes) and ferns (pteridophytes) are considered as amphibians of plant kingdonm, because of the following reasons:
(i) The gametophyte of both bryophytes and pteridophytes lack cuticle covering, therefore they grow in moist habitat to prevent desiccation.
(ii) In absence of vascular tissues, all parts of the gametophyte are able to absorb water directly from moist habitat.
(iii) The flagellated sperms of both the groups require an external supply of water for swimming to reach archegonia for affecting fertilization.