The gametophyte is the conspicuous and dominant generation in bryophytes that we readily see. Although the thallose forms are very unlike mosses, many liverworts would probably be regarded as mosses by people not familiar with botany. This is especially the case in New Zealand where in some habitats liverworts are the dominant bryophyte. Any small green 'leafy' plant which is not a fern or a flowering plant, or a cone bearing plant is almost sure to be either a moss or a liverwort. Nevertheless, the forked venation of the filmy ferns will separate them immediately.
Bryophytes are very old land plants.
In New Zealand bryophytes range in size from less than 1 mm in diameter to some of the largest bryophytes in the world reaching up to 90 cm eg Dawsonia superba . Some bryophytes can survive periods of drought but ALL bryophytes require moisture of some form in order to reproduce. Their great dependence on a moist environment for survival is chiefly linked to the flagellated sperm cells which must swim to the egg cells of the archegonia. Bryophytes are attached to the ground or other substrate by delicate colourless, or brown thread-like structures termed rhizoids. These are similar to the root-hairs of higher plants, and the detail of their structure can be seen only under the compound microscope.