Grimmia trichophylla
Grimmia orbicularis
grimmia dry rock moss, hair-point grimmia
orb dry rock moss
2–4 cm, central strand present.
2–5 cm, central strand present.
clusters occasionally present in distal leaf axils.
absent.
loosely appressed, slightly twisted when dry, erecto-patent 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 distally, awns variable, short to long, smooth to denticulate, not conspicuously flattened at base, costa firm, projecting on abaxial side;
basal juxtacostal laminal cells long-rectangular (rarely short-rectangular), ± nodulose, thick-walled;
basal marginal laminal cells short- to long-rectangular, with thickened transverse walls;
medial laminal cells quadrate to short-rectangular, slightly sinuose, thick-walled;
distal laminal cells 1-stratose, occasionally with 2-stratose ridges.
appressed and twisted when dry, erect when moist, broadly lanceolate, abruptly contracted into awn, 2–2.5 × 0.4–0.6 mm, keeled, margins recurved in the middle of the leaf on one or both sides, awns short to long, smooth to denticulate, costa weak proximally, projecting on abaxial side;
basal juxtacostal laminal cells short- to long-rectangular, sinuose-nodulose, thick-walled;
basal marginal laminal cells short- to long-rectangular, straight, with thickened transverse walls;
medial laminal cells subquadrate, sinuose, thick-walled;
distal laminal cells 1-stratose.
arcuate, 2–4 mm.
arcuate, 2–3 mm.
dioicous.
autoicous.
occasionally present, exserted, oblong-ovoid, yellowish green to stramineous, striate when dry, exothecial cells thin-walled, annulus present, operculum rostrate, peristome teeth yellowish, papillose, deeply split and perforated.
usually present, exserted, bent down into the cushions by the arcuate setae, yellowish brown to chestnut brown, globose to ovoid, smooth to weakly ribbed, when dry and empty wide-mouthed, exothecial cells thin-walled, annulus present, operculum mammillate, peristome teeth orange, broad, cribrose and irregularly cleft at apex.
mitrate.
cucullate.
Grimmia trichophylla
Grimmia orbicularis
In North America, Grimmia 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, the species is common, and in contrast to G. trichophylla in 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 unfavorable 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 36. G. muehlenbeckii and 34. G. lisae (see discussions thereunder for identification details). Robust forms of G. trichophylla have been mistaken for G. austrofunalis (H. C. Greven 1997, 2003), which does not occur in North America. Although some of those plants have leaves of equal length along the stem, characteristic of G. austrofunalis, they also have both leaf margins recurved, and the medial and outer basal laminal cells are longer and more robust than in that species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Grimmia orbicularis is a thermophilous species with a preference for sunny, basic substrates. In North America it is known only from scattered localities in the Southwest. It may be confused with G. pulvinata, as both species form comparable hemispherical cushions and usually grow in the same habitat. However, they differ markedly in both gametophytic and sporophytic characters. Grimmia orbicularis has leaves with short- to long-rectangular basal juxtacostal cells with thick and nodulose lateral walls, and 1-stratose margins while G. pulvinata has leaves with quadrate to short-rectangular, thin-walled, basal juxtacostal cells and 2-stratose margins. Grimmia orbicularis has globose to ovoid capsules with broad, orange, cribrose and cleft peristome teeth, and mammillate opercula while G. pulvinata has obovoid capsules with fully developed dark red peristome teeth and rostrate opercula.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
CalFlora
MO Plants
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
