Cephalomitrion

Lithophytic, dioicous. Specialised asexual propagules absent. Stems black, becoming reddish-brown or purplish near apex, wiry, frequently but irregularly branched, with two ranks of lateral leaves; branches emerging from stem abaxially and with a collar of tissue at base. Lateral leaves rounded-quadrate in outline, bifid, transverse, concave adaxially, tightly appressed to stem and difficult to distinguish except near apex, distant except near stem apex where becoming contiguous or imbricate, entire to slightly crenulate by bulging marginal cells, reddish-brown; lobes triangular, acute to rounded at apex. Leaf cells irregular-polygonal, smooth, thick-walled, becoming thinner toward base and margins, without distinct trigones, unistratose, with 1–8 oil bodies; oil bodies spherical to ovoid, very faintly granular. Androecia on main stem and branches, with 4–8 saccate bracts, each with one antheridium. Sporophyte terminal on main stem and branches, surrounded by a perianth; perianth ovoid-oblong, deeply 4–5-plicate, with a broad and crenulate mouth; capsule short-ellipsoid or ovoid, bistratose; elaters bispiral; spores globular, smooth or nearly so.