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grimmia dry rock moss

hartman's dry rock moss

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in ascending, dichotomously branched patches, green.
Stems

1–3 cm, central strand strong.

2–8 cm, central strand absent.

Gemmae

in clusters, mulberry- or raspberry-shaped, brown, borne on leaf apices, usually present.

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.

slightly contorted with often secund apices when dry, distal leaves usually falcate-secund when moist, broadly lanceolate, tapering to an acuminate apex, 2.5–4.5 × 0.4–0.6 mm, keeled, margins usually recurved on one side, awns very short, denticulate, costa firm, projecting on abaxial side;

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

basal marginal laminal cells quadrate, thickened transverse walls;

medial laminal cells quadrate to short-rectangular, slightly sinuose, thick-walled;

distal laminal cells 1-stratose, margins 2-stratose.

Seta

straight, (1–)2–4 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.

extremely rare, exserted, yellowish green, clavate-obloid, smooth, exothecial cells thick-walled, annulus present, operculum rostrate, peristome teeth orange, deeply split, perforated distally, papillose.

Calyptra

mitrate.]

[seta straight to flexuose, 3–4 mm.

Grimmia longirostris

Grimmia hartmanii

Habitat Exposed, dry, acidic granite and quartzite Shaded boulders, especially granite, in woodlands
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] low to moderate elevations (100-1500 m) [low to moderate elevations (300-4900 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
UT; VT; PE; QC; Eurasia; n 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 hartmanii is principally a lowland species, occurring in the mountains up to 1500 m. With the separation of G. anomala from it, G. hartmanii is much less common in North America than was previously thought. It is known principally from the Northeast. Although it is usually found in densely shaded habitats, in areas with high humidity it can establish itself in exposed sites. It more closely resembles some species of Racomitrioideae than it does species of its own genus, but it may be recognized by the usually spreading falcate-secund distal leaves, the very small awns, and the terminal clusters of brown gemmae, which are conspicuous and usually present. Capsules are extremely rare, and are unknown in North America.

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

Source FNA vol. 27, p. 239. FNA vol. 27, p. 251.
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. 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
Name authority Hooker: Musci Exot. 1: plate 62. (1818) Schimper: Syn. Musc. Eur., 214. (1860)
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