4. Pseudochorisodontium mamillosum (C. Gao & Z.-W. Ao) C. Gao, D. Vitt, X. Fu & T. Cao, comb. nov. 瘤叶无齿藓 liu-ye wu-chi xian
Dicranum mamillosum C. Gao & Z.-W. Ao, Bull. Bot. Lab. N.-E. Forest. Inst., Harbin 7:98. 1980. Type. China: Xizang, Ya-dong Co., M. Zang 426 (holotype KUN; isotype IFSBH).
Plants large to fairly robust, 6–10 cm high, yellowish green or dull green, shiny, in dense tufts. Stems erect, often dichotomously branched, densely tomentose below. Leaves loosely appressed or weakly flexuose- crispate when dry, erect-spreading when moist, ca. 6 mm long, gradually to rather abruptly narrowed from an oblong-ovate base to a slender, subulate acumen, the acumina about as long as the leaf base; margins plane, serrulate in the upper 1/3; costa slender, occupying ca. 1/8–1/6 the leaf base width, subpercurrent to percurrent, serrate at back near the apex; upper cells irregularly rounded quadrate, incrassate, not porose, coarsely papillose on both surfaces; basal cells elongate, nearly rounded rectangular, thick-walled, porose; alar cells well differentiated, 4–5 stratose, slightly inflated, yellowish brown. Dioicous. Male plants dwarfed. Perichaetial leaves highly convolute-sheathing, abruptly narrowed to a short, subulate acumen. Setae solitary, rarely double, straight, ca. 2 cm long, yellowish brown; capsules erect, cylindric, ca. 3 mm × 0.8 mm; opercula erect, long-rostrate, ca. 2 mm long or as long as the urns; peristome teeth absent. Spores 12–15 µm in diameter, brownish.