Monocarpaceae

Ephemeral, terrestrial on salt pans, monoicous. Specialised asexual propagules absent. Plants comprising a thallus; thallus pouch-like around carpocephalum when mature, adaxially with open air chambers formed by unistratose septa that lack a roofing epidermis and air pores; air chambers without photosynthetic filaments; thallus cells quadrate or pentagonal, thin-walled, without oil bodies. Abaxial scales absent. Rhizoids smooth, few abaxially at base of thallus, hyaline. Antheridia borne on floor of open air chambers on adaxial thallus. Sporophytes enclosed within short-stalked globose carpocephalum; carpocephalum initially much larger than capsule, but eventually only slightly larger, with air chambers, with 6–8 sided air pore in the epidermis overlying a square air pore in the hypodermis; stalk without rhizoid furrows; involucres absent; pseudoperianths absent. Seta short, on globose foot. Capsule cleistocarpous, unistratose; elaters absent. Spores densely echinate, hemispheric, pale to blackish-brown, shed singly; proximal face without triradiate ridge and less tuberculate, with or without a prominent, mostly unornamented border.