Polytrichastrum alpinum |
Polytrichastrum alpinum var. sylvaticum |
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alpine haircap, alpine polytrichastrum moss |
stiff-leaf haircap moss |
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Habit | Plants very variable in size, small to robust, dull green or brownish green, reddish with age, in loose or compact tufts. | |||||||||||||
Stems | (1–)4–6(–14) cm, densely leafy above, often leafless and thread-like below, simple or sparingly to fasciculately branched. |
to 14 cm, simple or sparingly branched. |
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Leaves | (4–)5–8(–19) mm, loosely to densely imbricate, erect-spreading and subtubulose when dry, erect-spreading to widely spreading when moist; sheath ± nitid, elliptic to obovate, with tapering shoulders (in var. fragile contracted above the sheath and the blade caducous), broadly hyaline-margined; blade linear-lanceolate, the apex narrowly acute to finely acuminate; marginal lamina 2–5 cells wide, erect, coarsely serrate with multicellular teeth, distantly serrulate to subentire; costa excurrent, ending in a short, brownish, toothed awn; lamellae 5–8 cells high, entire in profile, the marginal cells with the free wall appearing greatly thickened, the marginal cells in section enlarged, yellowish to dark brown, ovate to narrowly ovate, the lateral walls strongly thickened, the lumen narrowly pentagonal and pointed at the apex, coarsely papillose; median cells of sheath 40–60(–80) × 6–12 µm, elongate-rectangular, thin-walled; cells of the marginal lamina 10–15 µm, subquadrate, sometimes transversely elongate; perichaetial leaves scarcely longer than the stem leaves. |
(9–)12–14(–19) mm, coarsely toothed. |
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Seta | (1–)3–5 cm, brownish. |
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Capsule | various, (1.5–)3–5(–8) mm, terete, narrowly cylindric to oblong-cylindric and curved, ovate-cylindric, or ovoid to almost spherical, suberect to inclined to almost horizontal; hypophysis tapering, rugose, with numerous conspicuous stomata in a broad basal band; exothecial cells irregularly rectangular, not bulging or mammillose, thin spots absent, rather thick-walled; peristome 600 µm (teeth 150–250 µm), divided to 0.6–0.75, the teeth 45–50, with some teeth irregularly developed and unequal, pale to somewhat darker in the median line. |
5–8 × 1.5–2.2 mm, often ± zygomorphic and widest below the middle, suberect to inclined to almost horizontal. |
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Spores | 14–20 µm. |
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Polytrichastrum alpinum |
Polytrichastrum alpinum var. sylvaticum |
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Habitat | Soil, moist woods | |||||||||||||
Elevation | low to moderate elevations (0–1400 m) (low to moderate elevations (0–4600 ft)) | |||||||||||||
Distribution | Widely distributed in northern North America; and throughout cool temperate and boreal latitudes in the Northern Hemisphere; s temperate South America; Pacific Islands (New Zealand); Australia; Antarctica
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AK; OR; WA; BC |
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Discussion | Varieties 8 (4 in the flora). Polytrichastrum alpinum is highly variable in habit and plant size, dentition of the leaves, and capsule shape. However, all forms of the species are easily recognized by the entire-margined, coarsely papillose lamellae and terete capsules with smooth, non-pitted exothecial cells. The marginal cells of the lamellae in section are distinctive in shape and wall thickening, elegantly described by A. J. E. Smith (2004) as “strawberry-shaped.” The wall thickenings extend down the lateral walls, so that in profile the free margin appears to be much thicker-walled and the lumen more restricted than is actually the case. The marginal cells of P. sexangulare are similar in shape and wall thickening, but smooth. The only North American taxa of Polytrichaceae likely to be confused with P. alpinum when sterile are Meiotrichum lyallii and Pogonatum urnigerum. In P. urnigerum the marginal cells of the lamellae are shorter and broader at the apex with a pentagonal lumen; in M. lyallii the marginal cells seen in profile are irregularly striate and pitted rather than papillose. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Variety sylvaticum is a robust plant of the Pacific Northwest with stems to 14 cm high, sharply serrate leaves to as much as 19 mm, and large, plump, cylindric capsules, often ± zygomorphic. The type was collected by Menzies somewhere on the Northwest coast; Pogonatum macounii was collected in a ravine at 1370 m on Vancouver Island. Polytrichum alpinum var. campanulatum has large, ovoid-gibbous, almost horizontal capsules and is probably distinct, but its distribution is poorly understood. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 27, p. 125. | FNA vol. 27, p. 127. | ||||||||||||
Parent taxa | Polytrichaceae > Polytrichastrum | Polytrichaceae > Polytrichastrum > Polytrichastrum alpinum | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Polytrichum alpinum, Pogonatum alpinum | Polytrichum sylvaticum, Pogonatum alpinum var. macounii, Pogonatum macounii, Polytrichum alpinum var. campanulatum, Polytrichum alpinum var. sylvaticum | ||||||||||||
Name authority | (Hedwig) G. L. Smith: Mem. New York Bot. Gard. 21(3): 37. (1971) | (Menzies) G. L. Smith: Sida 22: 547. (2006) | ||||||||||||
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