CEPHALOZIA Dumort.
Gametophyte mostly small or minute, usually close-creeping; stems branching ventrally or rarely laterally, often flagelliferous; leaves obliquely placed, succubous, bifid from one-third to over one-half their length ; leaf cells usually large, transparent, mostly hexagonal ; under-leaves usually wanting on the stems, often present on perianth-bearing branches. Perianth long, triangular, with a narrowed, toothed or ciliate mouth.
Sporophyte an oval or oblong-cylindric capsule on an ephem eral seta, varying in different species from 2 mm. to 2 cm. long.
The genus includes some sixty species well distributed, but best known from the North Temperate zone. Fourteen species are found in America north of Mexico. These can be distin guished by the following table, which has been constructed with special reference to material in which the perianth characters can not be seen :