The bifid leaves extend like wings on either side of the midrib, or may be folded upwards and pressed close together, giving the plants a ruffled appearance.

Although some thalloid liverwort species in the Pallaviciniaceae also possess a central conducting strand,[7] Haplomitrium differs in having a food-conducting layer and in producing no callose.

Schuster proposes that species distributed in the northern hemisphere "rafted" on the Indian subcontinent to Asia, then spread across the Bering Strait into North America.

The genus Treubia is restricted to the southern hemisphere, while Apotreubia has one species in New Guinea and another disjunct between eastern Asia and British Columbia.

The genus Haplomitrium exhibits a wider distribution, with species in both North and South America, northern and central Europe, the Himalayas, Japan, and Australasia.