Trichomanes is a genus of ferns in the family Hymenophyllaceae, termed bristle ferns.[2] The circumscription of the genus is disputed. All ferns in the genus are filmy ferns, with leaf tissue typically 2 cells thick. This thinness generally necessitates a permanently humid habitat, and makes the fronds somewhat translucent. Because of this membrane-like frond tissue, the plant is prone to drying out. “Filmy ferns” in the taxa Hymenophyllaceae grow in constantly wet environments. Many are found in cloud forests such as “Choco” in Colombia. There are also members of the taxa that can grow submersed in water.
The genus Trichomanes was first described by Carl Linnaeus in 1753.[1] Its status, like other genera in the subfamily Trichomanoideae, remains disputed. The Pteridophyte Phylogeny Group classification of 2016 (PPG I) accepts the genus as one of eight in the subfamily Trichomanoideae, saying that there are about 60 species.[3] As of October 2019[update], the Checklist of Ferns and Lycophytes of the World listed about 70 species.[1] Other sources, including Plants of the World Online as of October 2019[update], treated Trichomanes as the only genus in the subfamily Trichomanoideae, so that it included all the other genera, and had about 250 species.[4]