They are a group of simple land plants, well-adapted to moist habitats. The dominant generation is the gametophyte. The sporophyte is parasitic on the gametophyte. This stems from the embryo being retained in the female sex organ of the gametophyte. Many are pioneer plants, growing on bare rock.
Many mosses are quite resistant to desiccation.
They can lose water in the dry season, remain alive and then imbibe water when it rains. Similarly, many temperate mosses can survive freezing and thawing without damage. Being prostrate, Bryophytes have much of their surface in contact with the substratum and readily absorb moisture this way. Water often is drawn along the surface of these plants by capillarity and this external water movement is important. In certain mosses, specialised transport cells, hydroids and leptoids, analogous to the xylem and phloem of vascular plants, are found at the centre of the stem.