Plants in robust, loose, arched-ascending, readily disintegrating patches, brownish-green distally, blackish below. Stems 5--10 cm, central strand absent. Stem leaves loosely appressed when dry, patent when moist, broadly ovate-lanceolate, tapering to an acute, slightly toothed apex, 2--3 × 0.4--0.6 mm, keeled, margins recurved on both sides, awns absent, costa stout, projecting on dorsal side with two low wings; distal laminal cells 1-stratose, margins 2-stratose; medial laminal cells quadrate to rectangular, sinuous, thick-walled; basal juxtacostal laminal cells yellow, linear, sinuose, thick-walled; basal marginal laminal cells quadrate to short-rectangular, straight, slightly thick-walled. Gemmae absent. Sexual condition dioicous. Seta cygneous at maturity, flexuose when old, 3--5 mm. Capsule occasionally present, exserted, obloid, yellowish-green to yellowish-brown, plicate when empty, exothecial cells thin-walled, annulus present, operculum rostrate, peristome teeth purple, divided nearly to base into two partly adhering segments, papillose. Calyptra mitrate.

Dry and damp acidic rock; 0--2000 m; Greenland; Alta., B.C. Nfld.; Alaska, Idaho, Mont., Oreg., Wash.; Europe; Asia (China, Japan); n Africa.

Grimmia ramondii occurs near sea level in Arctic areas and along the West Coast. In the latter region, however, it is more common in mid-elevation montane sites and may also be found above the tree line. Grimmia ramondii differs from most Grimmia species by its lack of awns, having only a slightly toothed apex, leaves with a winged costa and growing in tall loose patches. At first sight, G. ramondii has the habit of a Racomitrium. However, the sporophyte has an arcuate seta, and the winged costa is of the Grimmia type. Because of its habit and the absence of a central strand, G. K. Limpricht (1890) placed it, together with G. hartmanii and G. atrata in Dryptodon, a genus intermediate between Grimmia and Racomitrium. There are many other Grimmia species, however, without a central strand, and G. hartmanii and G. atrata have already been removed from Dryptodon, so there is no reason to maintain this monotypic genus. Grimmia ramondii may be confused with G. hartmanii, G. elatior and some Racomitrium species. However, the lack of awns and the Racomitrium-like areolation distinguishes it easily from the first two species. From Racomitrium it differs by its winged costa, 1-stratose lamina, and curved seta.