18. Leptodontium (C. Müll.) Hampe ex Lindb.   薄齿藓属 bo-chi xian shu

 Ö fvers. Förh. Kongl. Svenska Vetensk.-Akad. 21: 227. 1865.

 

Plants small to medium-sized to rather robust, 10–30(–50) mm, sometimes to 70 mm high, in loose tufts. Stems erect, forked or aggregately-branched; central strand absent. Leaves distantly arranged, contorted-curved when dry, erect-spreading or reflexed when moist, oblong-elliptic to oblong ovate-lanceolate, abruptly acute at the apex; margins entire, weakly recurved in the lower half, plane, serrulate in the upper half; costa stout, subpercurrent; upper leaf cells quadrate to hexagonal or rounded-hexagonal, thin- or thick-walled, multi-papillose; basal cells larger, smooth, yellowish or hyaline. Dioicous. Perichaetial leaves rather larger, sheathing at the base. Setae elongate, slender, sometimes aggregated; capsules cylindrical, erect or curved; annuli differentiated, consisting of several rows of cells, deciduous; peristome teeth linear-lanceolate, deeply divided, papillose or obliquely striate, basal membrane absent, rarely with properistome; opercula conic-rostrate, with long-beak. Spores yellowish, finely papillose.

1. Plants usually less than 20 mm high; leaves oblong-ovate, abruptly acute at the apex, not reflexed; upper margins serrulate................................................................................................................................................... 2

1. Plants usually more than 30 mm high; leaves ovate- to elliptic-lanceolate, gradually acute to acuminate, reflexed from the middle; upper margins irregularly serrate............................................................................ 3

2. Stems densely foliate; leaf cells strongly thick-walled; margins bodered by several rows of pale cells..

2. Stems loosely foliate; leaf cells thin-walled; margins not bordered..................................... 2.L. handelii

3. Leaf cells ca. 20 µm in diameter, densely covered with branched (bifid) papillae.............. 3. L. scaberrimum

3. Leaf cells less than 10 µm in diameter, with several simple, small papillae...................... 4. L. viticulosoides