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grimmia dry rock moss

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in hoary tufts, brownish green.
Stems

1–3 cm, central strand strong.

0.3–1 cm.

Gemmae

clusters of globular, brown, multicellular gemmae abundantly present on the adaxial side of the distal lamina.

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 to broadly oblong-lanceolate, 1–1.5 × 0.5–0.6 mm, larger towards stem tips, not keeled, frequently plicate in extreme apex, margins plane, incurved distally, long-awned, decurrent, costa weak proximally, broadened and deeply channeled distally;

basal juxtacostal laminal cells rectangular, straight, with thin walls;

basal marginal laminal cells rectangular, with thick transverse walls and thin lateral walls, hyaline in 3–4 rows;

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

distal laminal cells 1-stratose with 2-stratose ridges, in apex entirely 2-stratose.

Seta

straight, (1–)2–4 mm.

Sexual condition

cladautoicous, perichaetial leaves not enlarged.

probably dioicous, gametangia not seen.

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.

unknown.

Grimmia longirostris

Grimmia shastae

Habitat Exposed, dry, acidic granite and quartzite Volcanic rock
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] high elevations (3500 m) [high elevations (11500 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
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from FNA
CA
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 shastae is known only from Mt. Shasta. Its discovery demonstrates that the bryoflora of California is still not fully known. It also shows that the state is exceptionally rich in endemic species of Grimmia: G. mariniana, G. nevadensis, G. serrana, and G. shastae. Because of its abundantly present gemmae on the adaxial surface of the distal lamina, the latter is not likely to be confused with any other species of the genus. While gemmae are not rare in Grimmia, they are usually produced on leaf tips (G. anomala, G. hartmanii), on the abaxial side of the leaf (G. torquata, G. trichophylla), or in leaf axils (G. trichophylla, G. muehlenbeckii). In no other Grimmia species are gemmae produced in clusters on the surface of the adaxial lamina at the distal part of the leaf. The position of the species within the genus is not clear. Although its leaf form and areolation demonstrate its similarity to G. tergestina (subg. Litoneuron), the longitudinal plicae in the most distal leaves align it with G. caespiticia (subg. Guembelia). Sinuose laminal cell walls, characteristic of Grimmia, are only weakly present.

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

Source FNA vol. 27, p. 239. FNA vol. 27, p. 258.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Undetermined
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. 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) Greven: Grimmias, 208. 2003 (as shastai),
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