Grimmia trichophylla Greville, Fl. Edinensis. 235. 1824.
Authors: Roxanne I. Hastings & Dr. Henk C. Greven
Plants in dense to loose patches, yellowish-green to dark green. Stems 2--4 cm, central strand present. Stem leaves loosely appressed, slightly twisted when dry, erectopatent when moist, lanceolate to oblong-lanceolate, tapering to acute apex, 2--3.5 × 0.3--0.4 mm, usually sharply keeled, margins recurved on one or both sides, plane to erect above, awns variable, short to long, smooth to denticulate, not conspicuously flattened at base, costa firm, projecting on dorsal side; distal laminal cells 1-stratose, occasionally with 2-stratose ridges; medial laminal cells short-rectangular, slightly sinuose, thick-walled; basal juxtacostal laminal cells elongate to linear, ± nodulose, thick-walled; basal marginal laminal cells rectangular with thickened transverse walls. Gemmae clusters of gemmae occasionally present in distal leaf axils. Sexual condition dioicous. Seta arcuate, 2--4 mm. Capsule occasionally present, exserted, oblong-ovoid, yellowish-green to straminous, striate when dry, exothecial cells thin-walled, annulus present, operculum rostrate, peristome teeth yellowish, papillose, deeply split and perforated. Calyptra mitrate.
Dry, acidic rock; 200--2000 m; B.C.; Calif., Okla., Oreg.; Mexico; Eurasia; Pacific Islands (Hawaii); Australia.
In North America, G. trichophylla is principally a lowland species, occurring in the mountains up to about 1000 m., rarely higher. In the southern hemisphere, it may be found up to 4000 m. In New Zealand, G. trichophylla is a common species that, in contrast to North America, frequently bears capsules. The New Zealand plants are usually smaller than American specimens, and the leaves are frequently contorted. The nearly cosmopolitan G. trichophylla has many phenotypes and numerous subspecies and varieties have been described. In damp and shaded habitats, the awns may be short, just as in dry unfavourable habitats at high altitudes, where stunted specimens may occur with small short leaves and reduced awns, or even with muticous leaves. Grimmia trichophylla has frequently been confused with related species such as G. muehlenbeckii, G. lisae and G. austrofunalis. The sharply keeled, lanceolate leaves with recurved margins and merely 1-stratose lamina will usually distinguish G. trichophylla.