卵叶盐土藓

Pterygoneurum ovatum is the most common species of the genus and serves to stabilize arid soils (S. Flowers 1973). The setae may reach 3 mm. Faint thickenings reminiscent of a rudimentary peristome can sometimes be found associated with spore sac remnants dug out of the operculum, and the laminal distal cells may by simply papillose abaxially as in P. lamellatum. R. T. Wareham (1939) found the characters of Pterygoneurum ovatum var. incanum Juratzka, the long awns and short setae, inconstant in both American and European material.

Leaves with distal lamina smooth or rarely papilose; awn smooth or rarely with a few teeth; lamellae 8-16 cells in height, not lobed, seldom bearing filaments. Capsule stegocarpous, emergent to exerted, ovoid, annulus present, operculum cells in straight rows; eperistomate. Calyptra cucullate or rarely mitrate.

Plants 1–2 mm high, green or yellowish green, bulbiform, in thin tufts. Stems very short, erect, simple or branched at the base. Leaves appressed when dry, weakly spreading when moist, ovate to triangularly ovate, broadly concave, 1.0–1.7 mm long with the awn; margins plane or weakly incurved; costa ending in a smooth long awn, shorter than or nearly as long as the leaf base; with 2–4 rows of green lamellae on the ventral side of costa; upper leaf cells rounded quadrate to irregularly hexagonal, 10–14 µm in diameter, thin- to weakly thick-walled at the corners, smooth or occasionally with minute C-shaped papillae; basal cells rectangular, 26–67 µm x 10–24 µm, thin-walled, smooth. Setae 1.5–3.0 mm long; capsules shortly exserted, shortly cylindrical, 1.0–1.5 mm long, dark brown, wrinkled-plicate; annuli none; opercula conic-rostrate, with a short, oblique beak; peristome teeth absent. Calyptrae cucullate, smooth. Spores 20–30 µm in diameter, brownish, finely papillose.

Distribution: China, Mongolia, Russia, North America, and northern Africa.

Habitat: on dry soil over rocks.

Gymnostomum ovatum Hedwig, Sp. Musc. Frond., 31, plate 2, figs. 1-3. 1801