18. StruckiaC. Müll. 牛尾藓属 niu wei xian shu
Arch. Vereins Freunde Naturgesch. Mecklenburg 47: 129. 1893.
Plants robust, but often soft, grayish green, silver-glossy. Stems prostrate, irregularly branched; branches dense, erect, some shoots and branches attenuate and flagelliferous distally, or sometimes ending in stems with small ovate caducous leaves; rhizoids dense, reddish. Leaves densely imbricate when dry, erect or erect-patent when moist, ovate, narrowly acuminate or nearly filiform at apex; leaf margins slightly involute at base, entire or dentate above; costae double, very short; leaf cells narrowly rhomboidal or linear; alar cells in several rows, quadrate, hyaline. Autoicous. Inner perichaetial leaves erect, becoming lanceolate from a sheathing base. Setae slender, reddish or orange-yellow, frequently twisted when dry; capsules erect, ovoid, apophyses short, stomata present; opercula conic, round and blunt at tips; annuli broad, deciduous when mature; peristome usually single (endostome absent); exostome teeth narrowly lanceolate, short, yellow, densely papillose, nodule very long, sometimes perforate along median line. Spores densely papillose.