2. Lyellia R. Brown 异蒴藓属 yi shuo xian shu
Trans. Linn. Soc. London 12: 561. 1819.
Philocrya I. Hag. & Jens., Meddel. Grønland 15: 388. 1898.
Plants medium-sized to large, rigid, dark green or brownish green, in tufts or scattered. Stems erect, rarely branched, densely foliate above; rhizoids numerous at base. Leaves strongly crisped when dry, erect-patent when moist, lanceolate above, sometimes extending into a filiform acumen, distinctly sheathing at base; ventral lamellae longitudinally arranged; median leaf cells oval, thick-walled, often bistratose; cells at sheathing base hyaline, rectangular, thin-walled, unistratose; margins single- or double-toothed; costa thick, reaching to the apex, grossly dentate above on the leaf back. Dioicous. Perigonia discoid. Setae erect, rigid, usually reddish brown; capsules oblate-ovoid or oblate-globose, sharply keeled or arching keeled, dorsally or ventrally distinct or symmetrical, horizontal or oblique; mouth constricted; peristome absent; stomata at base of capsules; opercula conic, often with short or long hooked beaks. Calyptrae small, cucullate, smooth, only covering the beaks. Spores spherical or oval, verrucose.