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grimmia dry rock moss

dingy grimmia, onecolor dry rock moss

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in dense to loose patches, pale green to red-brown.
Stems

1–3 cm, central strand strong.

1.5–4(–5) cm.

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 oblong-lanceolate to ligulate from an ovate base, 1.5–2.5 × 0.5–0.7 mm, both margins incurved, intermarginal bands absent, often sheathing, muticous, cucullate, obtuse-rounded, costa narrow proximally;

basal juxtacostal laminal cells short-rectangular, straight, thick lateral walled, pale yellow;

basal marginal laminal cells short-rectangular, straight, thick lateral walled, pale yellow, hyaline;

medial laminal cells rounded to quadrate, straight, thick-walled;

distal laminal cells 2–3-stratose, rounded, thick-walled.

Seta

straight, (1–)2–4 mm.

straight to slightly sigmoid, 2–4 mm.

Sexual condition

cladautoicous, 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, brown, oblong-ovoid, exothecial cells short-rectangular, thin-walled, stomata present, annulus of 2–3 rows of rectangular, thick-walled cells, operculum long-rostrate, peristome perforate and split in distal half.

Calyptra

mitrate.

Perichaetial

leaves enlarged.

Grimmia longirostris

Grimmia unicolor

Habitat Exposed, dry, acidic granite and quartzite Cracks of wet acidic, siliceous rocks especially along streams or splash zones of lake shores
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] moderate to high elevations (200-2000 m) [moderate to high elevations (700-6600 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; CA; ME; MI; MN; NY; VT; BC; NF; ON; QC; Greenland; Eurasia; Africa (Ethiopia)
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.)

In Canada, Grimmia unicolor is found predominantly around the Great Lakes of southern Ontario eastward into southwestern Quebec, with a disjunct site in Newfoundland. In the United States, it is also commonly found in the Great Lakes region and extending eastward into southwestern Maine. The disjunct sites in British Columbia and on the Seward Peninsula may be a Beringial link with populations in Asia, where this species is widely distributed, and in northern Europe. Grimmia unicolor is often found in the splash zone of rocky shorelines, especially cliffs, and along rivers. This habitat is rarely occupied by other species of the genus, except for G. olneyi. Grimmia unicolor is readily distinguished from other species in the subgenus by its leaf morphology. Its leaves are oblong-lanceolate to ligulate, with an obtuse, rounded apex which is muticous. Grimmia olneyi has an acute leaf apex with long awns, and its basal marginal cells are quadrate, contrasting with the rectangular cells of G. unicolor. Sporophytically, G. unicolor typically has a straight seta while that of G. olneyi is sigmoid. Grimmia unicolor has a much narrower costa proximally and lacks an awn, in marked contrast to the broad costa and robust awn of G. laevigata. The leaf shapes of these two species are distinct, with G. unicolor having a pronounced ovate base and narrow leaves tending towards being ligulate, while G. laevigata has broadly oblong-ovate leaves without a shoulder separating the distal and proximal lamina.

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

Source FNA vol. 27, p. 239. FNA vol. 27, p. 243.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Litoneuron
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. torquata, G. trichophylla
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) Hooker: in R. K. Greville, Scott. Crypt. Fl. 3: plate 123. (1824)
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