Rauiella praelonga (schimp. ex Besch.) Wijk & Margad.

Plants wiry, slender to rather robust, mostly densely cespitose, pale green to sordid green to dark green, often with a yellowish, reddish, or brownish tinge. Ramification mostly rather regularly pinnate, occasionally irregular; branches horizontally spreading to erect, and then often all pointing in the same direction. Stem creeping to arching, up to c. 7 cm long; cross section consisting of c. 4-5 rows of small, incrassate, external cortical cells, c. 4-5 rows of large, rather thin-walled internal cortical cells, and a small group (c. 3 cells across) of very small, thin-walled central cells. Paraphyllia dense, obliquely spreading to almost appressed, directed towards the stem apex, mostly lanceolate and 1-2 cells wide, simple or lobed near their base; margin crenulate-mamillate; cells pluripapillate; terminal cell rounded to truncate, pluripapillate. Pseudoparaphyllia resembling the paraphyllia but bigger sized and more strongly ramified. Stem leaves 0.4-0.8(-0.9) mm by 0.3-0.6 mm, cordate-ovate to broadly cordate-ovate, imbricate, loosely appressed and incurved when dry, spreading when moist, concave, strongly keeled; apex gradually to abruptly narrowly acuminate, fragile, somewhat flexuose and near the stem apex more or less homomallous when dry; margin in the basal part of the leaf mostly broadly recurved and mamillate-crenulate, in the acumen flat or nearly so and less strongly crenulate; costa very strong, yellowish, ending in the acumen, adaxially lying in a deep furrow, abaxially strongly prominent, distal abaxial cells small, isodiametrical, strongly crenate-mamillate and low-papillate; lamina cells c. 8 µm across, isodiametrical or nearly so, rounded-angular, with incrassate walls, strongly mamillate and bearing several often indistinct low and rounded papillae; cells of the acumen elongate, less strongly mamillate and papillate; terminal cell long, acute, smooth, translucent and contrasting with the opaque lower cells. Branches up to c. 7 mm long, rigid when dry, often attenuate, in majority simple, but the longer ones often pinnate and assuming stem-nature; paraphyllia scattered, mostly very few. Branch leaves up to c. 0.65 mm long, ovate, concave, mostly closely imbricate and strongly keeled when dry, spreading when moist; apex acute to very short-acuminate; margin mostly recurved at one side of the leaf at least, mamillate-crenulate; costa strong, ending in the acumen, adaxially lying in a deep furrow, ab axially strongly prominent and for the greater part of its length rough and covered by short cells; lamina cells c. 5-8 µm across, resembling those of the stem leaves, but more strongly mamillate and papillate; terminal cell as in the stem leaves, but mostly short-conical. Autoicous. Gametoecia situated on the stem and the basal part of stem-like branches. Inner perichaetial leaves up to c. 3.5 mm long, lanceolate, sheathing, gradually to abruptly narrowed to a long subula; margin entire; costa ill-defined, ending in or with the subula; cells elongate to linear. Seta (5-)8-15 mm long, mostly reddish or orange, occasionally brownish, smooth. Theca (0.4-)0.9-1.5 mm long, elliptical, orange or brownish, curved and strongly asymmetrical, almost erect to almost horizontal. Peristome as in Thuidium; endostome cilia mostly simple, but in each capsule some are grouped in 2-s or 3-s. Spores c. (13-)15-21 µm across, subspherical, finely papillose. Operculum low-conical, often short-rostellate. Calyptra c. 1.5-2.0 mm long, cucullate, naked.