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grimmia dry rock moss

montane dry rock moss, sun grimmia

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in hoary cushions, yellow-green to dark blue-green, sometimes almost black.
Stems

1–3 cm, central strand strong.

1–1.2(–1.5) 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.

narrowly lanceolate, rarely ovate-lanceolate, 1–2 × 0.3–0.6 mm, concave-keeled, not plicate, margins plane, usually narrowly incurved distally, awn 0.2–1.3 mm, costal transverse section not prominent to prominent, semicircular;

basal juxtacostal laminal cells short- to long-rectangular, straight, thick-walled;

basal marginal laminal cells quadrate to short-rectangular, straight, thick-walled, not hyaline;

medial laminal cells rounded, thick-walled;

distal laminal cells 2-stratose, not bulging, marginal cells 2-stratose, not bulging.

Seta

straight, (1–)2–4 mm.

straight, 2–3 mm.

Sexual condition

cladautoicous, perichaetial leaves not enlarged.

dioicous, perichaetial leaves not enlarged.

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.

occasionally present, exserted, yellow to brown, oblong, exothecial cells rectangular, thin-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum rostellate, peristome present, fully developed, split and perforated in distal half.

Grimmia longirostris

Grimmia montana

Habitat Exposed, dry, acidic granite and quartzite Exposed acidic granite and sandstone
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] moderate to high elevations (900-4000 m) [moderate to high elevations (3000-13100 ft)]
Distribution
from FNA
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
[WildflowerSearch map]
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; NU; ON; YT; Mexico; Greenland; Europe; Africa
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.)

Grimmia montana is widespread and common on acidic rock in the warm, dry, western interior of North America from southern British Columbia and Alberta southward to California and Colorado. It is very rare at higher latitudes, with outliers known from Alaska, southern Yukon, and northern British Columbia, and a few populations from Greenland and Baffin Island. It is not known from the interior Great Plains, which are largely calcareous. As reported by J. Muñoz (1998b), it is surprisingly absent from seemingly suitable sites in eastern North America. Because its leaf margins can be either plane and/or incurved, it is most commonly confused with G. donniana and G. alpestris, which have plane and incurved margins, respectively. Grimmia montana is readily separated from G. donniana because it is dioicous and lacks stomata, whereas G. donniana is autoicous and has stomata. Gametophytically, G. montana has quadrate to short-rectangular basal marginal laminal cells with thickened transverse walls, while G. donniana has long-rectangular cells with thin walls. Separating G. montana and G. alpestris can be difficult; they have broadly overlapping distributions and both are dioicous and lack stomata. Grimmia alpestris often has bulging, mammilose laminal cells that easily separate it from G. montana, but some stems have leaves that lack this feature. Specimens of G. montana can then be identified by their basal leaf areolation. The basal juxtacostal laminal cells of G. montana tend to be significantly longer than the marginal cells and the two regions are usually distinct. In contrast, G. alpestris tends to have a uniform basal areolation, composed of quadrate to short-rectangular cells.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 239. FNA vol. 27, p. 233.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia
Sibling taxa
G. alpestris, G. americana, G. anodon, G. anomala, G. arizonae, G. atrata, G. attenuata, G. brittoniae, G. caespiticia, G. crinitoleucophaea, G. donniana, G. elatior, G. elongata, G. funalis, G. hamulosa, G. hartmanii, G. incurva, G. laevigata, G. leibergii, G. lesherae, G. lisae, G. mariniana, G. mollis, G. montana, G. moxleyi, G. muehlenbeckii, G. nevadensis, G. olneyi, G. orbicularis, G. ovalis, G. pilifera, G. plagiopodia, G. pulvinata, G. ramondii, G. reflexidens, G. serrana, G. sessitana, G. shastae, G. teretinervis, G. torquata, G. trichophylla, G. unicolor
G. alpestris, G. americana, G. anodon, G. anomala, G. arizonae, G. atrata, G. attenuata, G. brittoniae, G. caespiticia, G. crinitoleucophaea, G. donniana, G. elatior, G. elongata, G. funalis, G. hamulosa, G. hartmanii, G. incurva, G. laevigata, G. leibergii, G. lesherae, G. lisae, G. longirostris, G. mariniana, G. mollis, G. moxleyi, G. muehlenbeckii, G. nevadensis, G. olneyi, G. orbicularis, G. ovalis, G. pilifera, G. plagiopodia, G. pulvinata, G. ramondii, G. reflexidens, G. serrana, G. sessitana, G. shastae, G. teretinervis, G. torquata, G. trichophylla, G. unicolor
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 G. arctophila, G. brachydon, G. jamesii, G. montana var. brachydon, G. tenella, Guembelia tenella
Name authority Hooker: Musci Exot. 1: plate 62. (1818) Bruch & Schimper: Bryol. Europ. 3. 128. (1845)
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