2. Tortella humilis (Hedw.) Jenn.   纽藓 niu xian

Plants small, ca. 1 cm high, yellowish green, in loose tufts. Stems erect, usually simple. Leaves strongly crisped when dry, erect-spreading or reflexed when moist, ligulate to narrowly oblong, often channeled above, narrowly acute or bluntly apiculate, somewhat sheathing at base; margins plane or somewhat undulate or narrowly incurved, entire to weakly crenulate with projecting papillae; costa percurrent or ending just below the apex; upper leaf cells quadrate to hexagonal, unistratose, pluripapillose; basal cells often sharply differentiated, rectangular, smooth, forming a V-shaped base. Autoicous. Sporophytes not seen.