Plants in dense patches, reddish brown to blackish green. Stems 1--4 cm, central strand present. Stem leaves lanceolate, keeled, not plicate, one margin commonly narrowly recurved, awns 0.1--0.5 mm, lower leaves muticous, costal transverse section weak at base, terete above; distal laminal cells 1-stratose, not bulging, marginal cells 2-stratose, not bulging; medial laminal cells short-rectangular, sinuose, thick-walled; basal juxtacostal laminal cells elongate and chlorophyllous, straight, somewhat thick-walled; basal marginal laminal cells rectangular with straight walls, often hyaline. Perichaetial leaves not enlarged. Sexual condition dioicous. Seta straight to slightly curved, 1.5--2.5 mm. Capsule occasionally present, emergent to shortly exserted, yellow-brown, ovoid, exothecial cells variable, quadrate to rectangular, thin-walled, stomates present, annulus of 1--3 rows, operculum conical to rostrate, peristome present, fully developed, papillose.

Damp acidic volcanics and sandstone, high elevation forests to tundra; 400--2400 m; Greenland; Alta., N.W.T., Nunavut, Que.; Colo.; Mexico; Central America; South America; Eurasia; Africa.

Grimmia elongata is a widely distributed species mainly occurring above 2000 m, and with a preference for acidic sandstones and volcanic, damp, north-facing outcrops and ledges. It seems to be uncommon in North America, being collected only occasionally and from widely separated localities. However, the wide distribution of G. elongata across the Northern Hemisphere suggests that this species may be more common on this continent than available collections indicate. T. Cao and D. H. Vitt (1986) noted that in North America, specimens would most likely be confused with G. donniana, as they considered the two species to be closely related. However, these species are distinctly different in a number of easy to recognize characters: G. elongata is reddish brown, muticous or short-awned, has one leaf margin recurved and is dioicous. In contrast, G. donniana is green to black, long-awned, has plane leaf margins and is autoicous. These characters lead us to believe that these species are not closely related; H. C. Greven (2003) feels that G. elongata is most closely related to the Himalayan endemic G. redunca Mitten.