Grimmia longirostris |
Grimmia nevadensis |
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grimmia dry rock moss |
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Habit | Plants in compact cushions, yellow-green to dark olivaceous. | Plants in dense cushions, blackish green. |
Stems | 1–3 cm, central strand strong. |
0.5–0.7(–1) cm, central strand weak. |
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-lanceolate, 1.5–2 mm, both margins plane, incurved distally, intermarginal bands absent, awn 0.4–0.8 mm, costal transverse section prominent, semicircular; basal juxtacostal laminal cells short-rectangular, straight, thin-walled; basal marginal laminal cells short-rectangular, straight, with thick transverse and thin lateral walls, not hyaline; medial laminal cells quadrate to rounded, straight, thin-walled; distal laminal cells 2-stratose. |
Seta | straight, (1–)2–4 mm. |
straight, 0.9–1.1 mm. |
Sexual condition | cladautoicous, perichaetial leaves not enlarged. |
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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. |
commonly present, emergent, chestnut brown, ovate with distinct constriction below rim, exothecial cells rectangular, thick-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum conic, peristome absent. |
Calyptra | cucullate. |
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Perichaetial | leaves not enlarged. |
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Sexuality | dioicous. |
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Grimmia longirostris |
Grimmia nevadensis |
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Habitat | Exposed, dry, acidic granite and quartzite | Acidic sedimentary rocks |
Elevation | low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] | moderate to high elevations (1900-2500 m) [moderate to high elevations (6200-8200 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
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CA; NV |
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.) |
Of conservation concern. Grimmia nevadensis is a rare but locally abundant endemic, known only from the Sierra Nevada Mountains. Fertile specimens of it can be separated from G. mariniana by the absence of peristome teeth and by the chestnut brown capsules. Gametophytically, specimens of G. nevadensis contrast with those of G. mariniana by having a uniform basal areolation of short-rectangular cells with thin lateral walls, and margins not hyaline. If fertile, the immersed, eperistomate capsules will separate G. nevadensis from G. ovalis, G. alpestris, and G. montana. Sterile specimens can be separated from G. alpestris by the absence of bulging cells, and the uniformly short-rectangular, thin-walled basal laminal cells. While both G. nevadensis and G. montana have plane to incurved distal margins and both lack bulging laminal cells, the uniformly short-rectangular, thin-walled basal laminal cells and concave leaves will identify G. nevadensis. The latter is easily separated from G. arizonae and G. pilifera, in contrast with which it lacks stomata and peristome teeth, and its concave leaves with plane to incurved margins differ markedly from the keeled leaves with recurved leaf margins of the others. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 239. | FNA vol. 27, p. 245. |
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 | |
Name authority | Hooker: Musci Exot. 1: plate 62. (1818) | Greven: Bryologist 105: 273, fig. 1. 2002 (as nevadense), |
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