Grimmia torquata
Grimmia teretinervis
grimmia dry rock moss, twisted grimmia
grimmia dry rock moss
1–4 cm, small central strand present.
2–3 cm, central strand strong.
brown, multicellular, present on the abaxial side of distal leaves.
contorted when dry, patent when moist, lanceolate, 1.5–2 × 0.3–0.5 mm, keeled, margins slightly recurved proximally, plane distally, awns very short and smooth, occasionally absent, costa weak proximally, projecting on abaxial side;
basal juxtacostal laminal cells linear, extremely sinuose, thick-walled;
basal marginal laminal cells long rectangular, thin-walled, hyaline;
medial laminal cells rectangular, extremely sinuose, thick-walled;
distal laminal cells 1-stratose.
ovate-cordate to lanceolate, 0.6–1.2 × 0.2–0.5 mm, keeled, not plicate, margins plane, awn to 0.3 mm, often just hyaline tipped, commonly long-decurrent, costal transverse section prominent, circular distally;
basal juxtacostal laminal cells quadrate to short-rectangular, straight, thin- to thick-walled;
basal marginal laminal cells oblate to quadrate, straight, thick-walled, not hyaline;
medial laminal cells rounded-quadrate, thick-walled;
distal laminal cells 2-stratose, bulging, marginal cells 2-stratose, bulging.
slightly curved, straight when dry, 3–5 mm.
unknown.
dioicous.
dioicous, perichaetial leaves unknown.
sporadically present, exserted, ovoid, brown, smooth, striate when dry and empty, exothecial cells thin-walled, annulus present, operculum rostrate, peristome teeth yellowish, short, split in distal part, weakly papillose.
unknown.
mitrate.
Grimmia torquata
Grimmia teretinervis
Grimmia torquata is a montane-alpine species with a preference for shaded habitats. It grows in hemispherical cushions on steep, damp rock walls. Preferred substrates are granite, gneiss, quartzite, and schist. Its distribution reaches from near sea level in the Arctic to above 4000 m on Mexican and Hawaiian volcanoes. The species is easily recognized by its yellow-brown cushions of plants, which have contorted leaves when dry, and their brown gemmae, which are borne at the bases of older leaves. In densely shaded habitats, the cushions are light green; on exposed rock, they are usually brown. Although the species has a wide distribution, it is seldom present in quantity, usually growing in a small number of cushions in one habitat. Sporophytes are very rare worldwide and have not been found in eastern North America (H. A. Crum and L. E. Anderson 1981).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
As reported by R. R. Ireland (1982b), Grimmia teretinervis is widely scattered across North America, but nowhere is it common. R. I. Hastings (2002) added several more Western collection locations to those reported by Ireland. Based on field observations and by correlating collecting localities with bedrock geology, Hastings proposed that the distribution of G. teretinervis in North America is largely correlated with the boundaries of ancient epicontinental seaways. These deposits have subsequently undergone faulting or were subjected to glacial-fluvial erosion. The ancient oceans provided the calcareous sediments, and the faulting and erosion created the steep exposures preferred by G. teretinervis. Sporophytes have never been observed for this species and, until reported by Ireland, antheridial plants also were unknown. Despite the lack of sporophytes, this species is readily identified by its unique costal structure, which is circular in transverse section. It commonly has thick-walled, bulging laminal cells and very short awns that are none-the-less often long-decurrent. These features give the plants a blackish brown, shiny thread-like appearance.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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