Bryophytes consist of mosses, liverworts, and hornworts. The members of this phylum generally live in more or less shady or perpetually moist places, where the danger of drying out is minimised. Some bryophytes inhabit bogs and swamp, while others grow in the cold regions of the world such as the tundras and on higher regions. Still others grow in deserts, near hot springs and in the tropics. In tropical rain forests, bryophytes occur abundantly as epiphytes on the leaves, branches and trunks of trees. Several species of bryophytes live in fresh water but none in marine.
The gametophytes of bryophytes are green and manufacture their own food; they are relatively large as compared to sporophytes, which obtain their food directly from the gametophytes. Some sporophytes are completely enclosed within the gametophyte tissue; others which are not, turn brownish at maturity. Rhizoids, which are colourless projections, anchor most bryophytes to their substrate. Unlike roots of vascular plants, these do not play any role in transportation.
The two major features that distinguish bryophytes from vascular plants are:
- They lack specialised vascular tissues which the vascular plants have
- The sporophytes are generally small, short-lived and draw their food from the gametophytes on which they are produced.