Mosses (bryophytes) and ferns (pteridophytes) are considered as amphibians of plant kingdom, because of the following reasons :
(a) The gametophyte of both bryophytes and pteridophytes lack cuticle covering, therefore grow in moist habitat to prevent desiccation.
(b) In absence of vascular tissues, all parts of the gametophyte are able to absorb water directly from moisty habitat.
(c) The flagellated sperms of both the groups require an external supply of water for swimming to reach archegonia for affecting fertilization. In this respect mosses and ferns resemble with amphibians of animal kingdom. Amphibian animals also require an external source of water for sperms to swim and fertilize the egg outside their body.