(Abrodictyum obscurum siamense)
Trichomanes is a large genus of ferns in the family Hymenophyllaceae, termed bristle ferns. Some botanists place it in its own family, Trichomanaceae. All ferns in the hymenophylloid clade are filmy ferns, with leaf tissue typically 2 cells thick. This thinness generally necessitates a permanently humid habitat, and makes the fronds somewhat translucent.