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grimmia dry rock moss

moxley's dry rock moss

Habit Plants in compact cushions, yellow-green to dark olivaceous. Plants in frequently extended mats, blackish green.
Stems

1–3 cm, central strand strong.

1–1.5 mm high, small central strand present.

Gemmae

absent.

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.

erect with slightly incurved tips when dry, erect-spreading when moist, oblong, broadly rounded and muticous at apex, 1.5–2 × 0.4–0.6 mm, keeled, margins plane to recurved, awns absent, only present in perichaetial leaves, costa weak proximally, projecting at abaxial side, perichaetial leaves longer and with awns;

basal juxacostal laminal cells short- to long-rectangular, straight, thin-walled;

basal marginal laminal cells short- to long-rectangular, thin-walled;

medial laminal cells rounded-quadrate, ± sinuose, thin- or thick-walled;

distal laminal cells 2-stratose.

Seta

straight, (1–)2–4 mm.

flexuose to arcuate, 1–1.5 mm.

Sexual condition

cladautoicous, perichaetial leaves not enlarged.

autoicous.

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.

usually present, exserted, chestnut brown, oblong-ovoid, wrinkled-plicate when dry, exothecial cells thin- to thick-walled, annulus present, operculum conical, peristome teeth yellowish, split and perforated, papillose.

Calyptra

cucullate.

Grimmia longirostris

Grimmia moxleyi

Habitat Exposed, dry, acidic granite and quartzite Dry acidic rock
Elevation low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] moderate elevations (500-1500 m) [moderate elevations (1600-4900 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
AZ; CA; NV; Mexico
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 moxleyi is endemic to the southwestern United States and northwestern Mexico. A thermophilous species from acidic rock, it is autoicous and usually richly provided with capsules. The species is characterized by growing in flat, easily disintegrating patches with short, keeled, muticous stem leaves that contrast with its much larger awned perichaetial leaves. J. Muñoz (2000) synonymized G. moxleyi with G. orbicularis. Although there are some similarities, G. orbicularis is much larger, grows in dense cushions on basic rock, has setae 2–3 mm, shiny, spherical capsules, and a mammilate operculum. Only the most proximal stem leaves of G. orbicularis are muticous and the basal juxtacostal cells have thick, nodulose walls.

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

Source FNA vol. 27, p. 239. FNA vol. 27, p. 254.
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. 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) R. S. Williams: in J. M. Holzinger, Musci Acroc. Bor.-Amer., 600. (1926)
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