Grimmia longirostris |
Grimmia teretinervis |
|
---|---|---|
grimmia dry rock moss |
grimmia dry rock moss |
|
Habit | Plants in compact cushions, yellow-green to dark olivaceous. | Plants in loose tufts, green-brown to reddish brown, shiny. |
Stems | 1–3 cm, central strand strong. |
2–3 cm, central strand strong. |
Leaves | ovate-lanceolate, 1.5–3 × 0.6–0.7 mm, keeled, one margin recurved proximally, not sheathing, awn 0.5–1.5 mm, costal transverse section prominent, reniform; basal juxtacostal laminal cells long-rectangular to linear, sinuose, thick-walled; basal marginal laminal cells short-rectangular, straight, with thick transverse and thin lateral walls, hyaline; medial laminal cells short-rectangular, sinuose, thick-walled; distal laminal cells 2-stratose, not bulging, marginal cells 2-stratose, not bulging. |
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. |
Seta | straight, (1–)2–4 mm. |
unknown. |
Sexual condition | cladautoicous, perichaetial leaves not enlarged. |
dioicous, perichaetial leaves unknown. |
Capsule | usually present, (emergent to) exserted, yellow, oblong-ovoid to cylindric, exothecial cells short- to long-rectangular, thin-walled, stomata present in 2–3 rows, annulus of 2 rows of rectangular, thick-walled cells, operculum long-rostrate, peristome present, fully-developed, split and perforate in distal half. |
unknown. |
Grimmia longirostris |
Grimmia teretinervis |
|
Habitat | Exposed, dry, acidic granite and quartzite | Moist calcareous sandstone, limestone and dolomite outcrops |
Elevation | low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] | moderate to high elevations (200-1700 m) [moderate to high elevations (700-5600 ft)] |
Distribution |
AK; AZ; CA; CO; ID; ME; MN; MT; NC; NH; NM; NV; OK; OR; SD; TX; UT; VT; WA; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; QC; SK; YT; Mexico; South America; Africa; Pacific Islands; Greenland; Eurasia; Central America (Costa Rica, Guatemala, Honduras); Australia
|
AK; AR; CO; MN; MO; MT; NV; OK; WI; AB; BC; NT; ON; QC; SK; YT; Europe |
Discussion | Grimmia longirostris is one of the most common species of the genus. It is most common in the eastern ranges of the Rocky Mountains, ranging from western Texas through the Canadian Rockies, and throughout much of Alaska. It is widely distributed in the Canadian sub-Arctic and Arctic, and is known from Greenland. With the exception of disjunct sites in Oklahoma and North Carolina, it is absent in the American Great Plains and Southeast. These latter areas are largely composed of calcareous rocks, a substrate avoided by G. longirostris. It is rare in coastal areas, becoming more common inland. As Grimmia affinis, G. longirostris has commonly been placed as a subspecies of G. ovalis. Despite G. Sayre’s (1951) resolution of the differences between these taxa, a large proportion of specimens in major herbaria in North America that are named G. ovalis are actually G. longirostris. However, G. ovalis is dioicous and has leaves with plane margins that are broadly concave distally, usually with a distinct ovate base and well-defined shoulders. In contrast, G. longirostris is autoicous, and has leaves with one recurved margin, that are narrowly keeled distally, with a poorly defined basal region, often without a distinct shoulder. These characters clearly separate these two taxa at the specific level. Hastings puts G. longirostris into a group that also includes G. arizonae and G. pilifera. Grimmia longirostris is separated from those two species by non-sheathing leaf bases, usually long-exserted capsules, and cladautiocous sexuality. Grimmia longirostris is further separated from G. pilifera by having a stem with a distinct central strand and a thin epidermis, a costal transverse section that is typically reniform, and leaves that are recurved on only one margin. Rare specimens of G. longirostris with immersed capsules in the American Southwest may be almost indistinguishable from G. arizonae. In extremely xeric environments, specimens become friable and break into individual strands, making determination of the cladautiocous sexuality impossible. In these circumstances identification will always be uncertain. However, the leaves of G. longirostris are not sheathing; they are only loosely attached to the stem and usually can be peeled off intact. In contrast, the leaves of G. arizonae are sheathing and strongly attached to the stem; they often break at the base when trying to remove them. The costal transverse sections of G. longirostris are characteristically reniform (J. Muñoz 1998) while those of G. arizonae are usually semicircular. However, gradations from semicircular to reniform are not uncommon. (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.) |
Source | FNA vol. 27, p. 239. | FNA vol. 27, p. 239. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | G. affinis, G. arctophila subsp. labradorica, G. catalinensis, G. catalinensis var. mutica, G. elata, G. ortholoma, G. ovalis var. affinis, G. ovata var. affinis, G. ovateoformis | Schistidium teretinerve |
Name authority | Hooker: Musci Exot. 1: plate 62. (1818) | Limpricht: Jahresber. Schles. Ges. Vaterl. Cult. 61: 216. (1884) |
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