Grimmia longirostris |
Grimmia arizonae |
|
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grimmia dry rock moss |
Arizonia dry rock moss |
|
Habit | Plants in compact cushions, yellow-green to dark olivaceous. | Plants in hoary tufts, olivaceous to dark blue-green. |
Stems | 1–3 cm, central strand strong. |
1–3 cm, central strand strong. |
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-lanceolate, 1.5–3 × 0.6–0.7 mm, keeled, one margin recurved proximally (occasionally both), sheathing, awn 0.5–1.5 mm, costal transverse section prominent, reniform to semicircular; basal juxtacostal laminal cells long-rectangular to linear, sinuose, thick-walled; basal marginal laminal cells short-rectangular, straight, 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. |
Seta | straight, (1–)2–4 mm. |
straight, 0.5–0.7 mm. |
Sexual condition | cladautoicous, perichaetial leaves not enlarged. |
dioicous, 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, immersed, yellow, oblong-ovoid, exothecial cells quadrate, thin-walled, stomata present in 2–3 rows, annulus of 2 rows of rectangular, thick-walled cells, operculum long-rostrate, peristome present, perforate in middle, split in distal half. |
Grimmia longirostris |
Grimmia arizonae |
|
Habitat | Exposed, dry, acidic granite and quartzite | Exposed, dry, basalt and acidic granite, rarely on sandstone |
Elevation | low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] | high elevations (1800-2700 m) [high elevations (5900-8900 ft)] |
Distribution |
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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AZ; CA; CO; KS; NM; OK; TX; 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.) |
Grimmia arizonae is endemic to the American Southwest and northern Mexico. It has a highly restricted distribution in North America, being found in mountainous areas in southeastern Arizona to the Rocky Mountain Front Ranges of western Texas, New Mexico, and Colorado. It has disjunct sites in western Oklahoma and central California. Grimmia arizonae is part of a group that includes G. longirostris and G. pilifera. Its sheathing leaf bases, dioicous sexuality and immersed capsules will separate it from G. longirostris. The separation of G. arizonae from G. pilifera, however, has often proven problematic. Grimmia pilifera has been described as having strongly keeled leaves and margins 2–3-stratose, thicker than the medial lamina. (e.g., H. A. Crum 1994c). H. C. Greven (1999) added usually with short-awned, ovate-lanceolate leaves. Grimmia arizonae has less keeled leaves and margins 2-stratose, not thicker than lamina. Greven noted its usually long awns and broadly lanceolate leaves. J. Muñoz (1999), however, synonymized these species, attributing any differences to geographical variations and sexual development. He reported that in eastern North America, and in shade, G. pilifera has long, acuminate apices and distinct ovate bases. In the West, and in sun, its leaves are lanceolate and without distinct bases. We would call these specimens G. arizonae. To Muñoz, the presence or absence of a central strand, is “too variable to be reliable;” he reported that fertile stems have a distinct strand, sterile stems have none. In contrast, in the present study, Hastings found the stem central strand reliable to separate these species. There is no correlation between sexual maturity and strand development; specimens of G. pilifera lack a central strand. Further, the stem epidermis is consistently twice as thick as it is in G. arizonae. Hastings found western specimens, in full sun, that lack a central strand typical of eastern specimens named G. pilifera. Many sterile specimens from Arizona have a central strand, but sterile or fertile, specimens in eastern North America do not have one. Based on these observations, G. arizonae and G. pilifera are not synonymous. Grimmia arizonae differs from G. pilifera by having a central strand, a thin epidermis, and 2-stratose distal lamina with 2-stratose not-thickened margins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 239. | FNA vol. 27, p. 240. |
Parent taxa | ||
Sibling taxa | ||
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. santaritae |
Name authority | Hooker: Musci Exot. 1: plate 62. (1818) | Renauld & Cardot: Rev. Bryol. 19: 85. (1892) |
Web links |