12. Dichodontium Bruch & Schimp. in B. S. G., Coroll. Bryol. Eur. 12. 1856.
裂齿藓属
Plants small to medium-sized, yellowish green to dark green, in compact or loose tufts. Stems erect, simple or sparsely branched, often by innovation, radiculose below; central strand present. Leaves contorted to crispate when dry, oblong-lanceolate to ligulate, bluntly acute to rounded-obtuse and irregularly dentate at the apex; margins entire; costa strong, ending below the apex or subpercurrent, with a median row of guide cells, a well developed dorsal stereid band, and a small ventral band in transverse section; upper laminal cells nearly quadrate to rounded-qudarate, papillose-mammillose on both surfaces; lower cells elongate, rectangular, smooth, transparent; alar cells not differentiated. Dioicous. Perichaetial leaves similar to the upper leaves. Setae elongate, stout, smooth; capsules oblong-ovoid, symmetric or slightly curved, erect or inclined, with or without struma; opercula obliquely rostrate; annuli absent; peristome teeth 16, reddish, divided halfway down, basal membrane low, vertically striate below, papillose above. Calyptrae cucullate, entire at base.
Dichodontium is very close to Oreoweisia, but it differs in having peristome teeth striate below, papillose above, and divided halfway down. Only one species was reported by C. Gao (1994) from China. However, Sakurai (1949) described a new species, Dichodontium integrum from Shanxi province, which is obviously an overlooked species from China. No specimen of this species is available for study; we can only provide a description from the type prologue.
