Grimmia longirostris |
Grimmia incurva |
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grimmia dry rock moss |
black grimmia, grimmia dry rock moss |
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Habit | Plants in compact cushions, yellow-green to dark olivaceous. | Plants in usually rounded cushions, green to blackish. |
Stems | 1–3 cm, central strand strong. |
1–2 cm, 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. |
incurved and moderately contorted when dry, spreading when moist, oblong- to linear-lanceolate, tapering to a slender and acuminate, often hyaline apex, 2.5–4.5 × 0.3–0.5 mm. |
Seta | straight, (1–)2–4 mm. |
arcuate, 1.5–2 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. |
occasionally present, emergent to exserted, yellowish, obloid, smooth or somewhat wrinkled when dry, exothecial cells thin-walled, annulus present, operculum conic to rostrate, peristome teeth orange, divided distally, papillose. |
Calyptra | mitrate. |
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Keeled | , margins plane or recurved proximally on one or both sides, awns short, often only mucronate, occasionally long and denticulate, costa projecting on abaxial side; basal juxtacostal laminal cells long-rectangular, slightly sinuose, thick-walled; basal marginal laminal cells short- to long-rectangular, thin-walled; medial laminal cells rectangular, nodulose, thick-walled; distal laminal cells 1-stratose, margins and apex 2-stratose. |
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Grimmia longirostris |
Grimmia incurva |
|
Habitat | Exposed, dry, acidic granite and quartzite | Shaded damp, acidic rock |
Elevation | low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] | moderate to high elevations (500-2500 m) [moderate to high elevations (1600-8200 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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CA; CO; ME; NH; NY; OR; SD; WA; AB; BC; LB; NB; YT; Greenland; Eurasia |
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.) |
The peculiar east-west disjunct distribution of Grimmia incurva in North America may reflect its preference for damp sites. Specimens have been collected in New England and in the Maritime Provinces, with a second widespread area running from the Yukon south through to California. It is uncommon in the continental interior. Grimmia incurva is a shade-loving subalpine species, characterized by rounded dark green cushions and linear, contorted leaves. The awns are visible only with a hand-lens. This species has a habit more like that of Dicranowesia crispula than of a Grimmia. H. A. Crum and L. E. Anderson (1981) reported immersed capsules, but that is not correct; they are clearly exserted (H. C. Greven 1995). Crum and Anderson also observed: “Specimens recorded from Maine can be considered a shade form of G. donniana.” However, this confusion extends beyond Maine. Greven renamed nearly all the G. donniana specimens from New York and New Hampshire in MICH to G. incurva. Hastings agrees that these specimens cannot be G. donniana because the leaf shape is virtually identical to that of G. incurva, being narrowly lanceolate and contorted. However, like G. donniana, and unlike G. incurva, the specimens are autoicous and the setae are straight. Rather than expanding the concept of either G. donniana or G. incurva to include these anomalous specimens, we propose that they represent an as yet unpublished species with a unique combination of characters. Hastings thus retains G. incurva as being dioicous and G. donniana as having oblong-lanceolate leaves. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 239. | FNA vol. 27, p. 252. |
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. curvifolia, G. torngakiana |
Name authority | Hooker: Musci Exot. 1: plate 62. (1818) | Schwägrichen: Sp. Musc. Frond. Suppl. 1(1): 90. (1811) |
Web links |