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grimmia dry rock moss

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in cushions or mats, yellow-green, glaucous-green to dark 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 to ovate-lanceolate, 1–1.8 × 0.2–0.6 mm, keeled, not plicate, margins plane proximally, incurved distally, awn 0.3–0.8 mm, costal transverse section prominent, semicircular;

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

basal marginal laminal cells quadrate to short-rectangular, straight, thick-walled, 1–2 rows hyaline or not hyaline;

medial laminal cells quadrate to short-rectangular, straight, thin-walled;

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

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, ovate to oblong-ovate, exothecial cells quadrate to short-rectangular, thick-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum conic to mammilate with a short obtuse beak, peristome present, fully-developed, split and perforated in distal half.

Grimmia longirostris

Grimmia alpestris

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 (360-3300 m) [moderate to high elevations (1200-10800 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
AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; Greenland; Eurasia
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 alpestris has a distribution similar to that of G. montana, being widespread and common on acidic rock in the warm, dry, western interior of North America from southern British Columbia and Alberta to California and Colorado. The other two North American species with bulging laminal cells, G. caespiticia and G. sessitana, both have capsules with stomata, readily separating capsulate specimens from G. alpestris. H. C. Greven (2003) reported that the capsules of G. alpestris are brown, with thick exothecial cell walls, and are smooth when empty, whereas those of G. sessitana are yellowish to light brown, with thin-walled exothecial cells, and are striolate when empty. The incurved margins and uniformly 2-stratose distal lamina of G. alpestris contrasts with the plane or one recurved margin and 1-stratose distal juxtacostal laminal cells of G. sessitana. The dioicous sexuality of G. alpestris also helps to separate these species. Some specimens of G. alpestris have leaves with streaks of thickened or multistratose cells; superficially these may appear to be plications. However, in transverse section they are readily separated from the truly plicate leaves of G. caespiticia. Furthermore, G. alpestris leaves are never cucullate, while those of G. caespiticia usually are. Grimmia alpestris is best separated from G. montana by its often bulging laminal cells and secondarily by its relatively uniform, quadrate to short-rectangular basal areolation. While G. donniana also has a uniform basal areolation, its cells are much longer and thin-walled, and its margins are plane throughout the length of the leaf.

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

Source FNA vol. 27, p. 239. FNA vol. 27, p. 234.
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. 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. 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
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 Trichostomum pulvinatum var. alpestre, G. donniana var. alpestris
Name authority Hooker: Musci Exot. 1: plate 62. (1818) (Weber & Mohr) Schleicher: Cat. Pl. Helv. ed. 2, 29. (1808)
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