烟杆藓科 yan gan xian ke
by Wang Mei-zhi, Li Xing-jiang, and Si He
Plants very small, annual, scattered or gregarious, usually extremely reduced. Protonemata abundant, green, branched, often persistent, in interwoven mats. Stems simple, very short, less than 1.0 mm long, pale brownish, with hyaline rhizoids. Leaves few, very small, membrane-like, soft, broadly ovate or ovate-lanceolate, often hyaline above, green at the base, less than 1 mm long; margins ciliate; costa absent; leaf cells lax, unistratose, oblong-hexagonal. Dioicous. Male plants minute, less than 0.5 mm high, resembling a clam shell, often hyaline, resting on the protonemata; antheridia globose. Sporophytes well developed, 1–2 cm high; perichaetial leaves not differentiated; paraphyses none. Setae elongate, ca. 1.5 cm long; stout, rigid, reddish, densely papillose, slightly inflated and with numerous rhizoids at the base; capsules grayish yellow or reddish brown, ovoid to oblong-ovoid, often differentiated into dorsal and ventral surfaces, flat or convex on the dorsal (upper) surface, swollen on the ventral (lower) surface, asymmetric, inclined to horizontal, narrowed at the mouth, necks short; stomata superficial; opercula bluntly conic; annuli weakly differentiated; peristome double; exostome short, consisting of 1–4 rows of concentric series of short, irregular, smooth or papillose cells; endostome often pale, consisting of a 16-plicate membrane-like, open cone. Calyptrae small, cucullate, conic or thimble-shaped, smooth. Spores spherical, small, 5–15 µm in diameter, papillose.