长蒴藓属

Plants small, light green to yellowish green, gregarious or in loose tufts. Stems erect, simple or rarely branched; central strand present. Leaves usually contorted when dry, oblong to oblong-ovate at the base, gradually to abruptly narrowed from the clasping base to a long awn or linear-subulate acumen; margins entire, usually recurved in the upper part; costa strong, subpercurrent to long-excurrent; upper cells small and somewhat obscure, subquadrate to short-rectangular; lower cells at the clasping base, elongate, thin-walled, smooth; alar cells not differentiated. Autoicous. Perichaetial leaves clearly larger than the vegetative ones. Setae elongate, straight, yellowish to yellowish brown; capsules suberect, usually curved above, cylindric, the neck slender, as long as or longer than the urns, usually strumose at the base; opercula obliquely long-rostrate; annuli simple or compound; peristome absent or present, with 16 linear-lanceolate teeth, usually undivided, perforate or forked, vertically striate on outer surface. Calyptrae cucullate, smooth. Spores 20–30 µm in diameter, subreniform, distinctly papillose.

Trematodon is characterized by having long-necked capsules and vertically barred peristome teeth. Gametophytically, it is similar to Dicranella and Ditrichum. Trematodon consists of some 80 species in the world. Nine species of it were previously reported from China. Many of the Chinese records were proved to be T. longicollis, and only two species were recognized by T. Cao and C. Gao (1988).

Lower Taxa

• Trematodon ambiguus (Hedw.) Hornsch.
• Trematodon longicollis Michaux.