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grimmia dry rock moss

grimmia dry rock moss, twisted grimmia

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in soft, readily disintegrating cushions, yellow-green to brownish, occasionally light green, blackish to red-brown inside.
Stems

1–3 cm, central strand strong.

1–4 cm, small central strand present.

Gemmae

brown, multicellular, present on the abaxial side of distal leaves.

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.

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.

Seta

straight, (1–)2–4 mm.

slightly curved, straight when dry, 3–5 mm.

Sexual condition

cladautoicous, perichaetial leaves not enlarged.

dioicous.

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.

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.

Calyptra

mitrate.

Grimmia longirostris

Grimmia torquata

Habitat Exposed, dry, acidic granite and quartzite Damp, frequently vertical faces of acidic rock
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] moderate to high elevations (200-4000 m) [moderate to high elevations (700-13100 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; NV; OR; WA; WY; HI; AB; BC; NL; NT; ON; QC; YT; Mexico; Eurasia; n Africa; Greenland
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 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.)

Source FNA vol. 27, p. 239. FNA vol. 27, p. 256.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Rhabdogrimmia
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. 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. 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. pellucida, G. prolifera, G. pseudotorquata, G. tortifolia
Name authority Hooker: Musci Exot. 1: plate 62. (1818) Drummond: Musc. Scot. 2: no. 28. (1825)
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