Schistidium apocarpum |
Schistidium robustum |
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schistidium moss |
robust grimmia, robust schistidium |
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Habit | Plants in open tufts or mats, olivaceous to brownish (black), sometimes with yellowish tones. | Plants in open to compact tufts, olivaceous, sometimes brownish or yellowish. |
Stems | 1.2–12 cm, central strand weak or absent. |
1–5 cm, central strand distinct. |
Leaves | erect or curved, rarely (falcate-) secund when dry, ovate-lanceolate, sharply keeled distally, (1.3–)1.7–2.5(–3.2) mm, 1-stratose or rarely 2-stratose in striae distally; margins usually recurved throughout or to just before the apex, usually denticulate distally, 1 or 2-stratose; apices acute or sub-obtuse; costa percurrent or excurrent as a smooth or weakly denticulate, occasionally decurrent awn, abaxial surface often papillose; basal marginal cells usually quadrate; distal laminal cells mostly short-rectangular, 8–10 µm wide, smooth, sinuose. |
erect or curved when dry, narrowly ovate-lanceolate to ovate-lanceolate, sharply keeled distally, 1.6–3 mm, 1-stratose, rarely with 2-stratose striae distally; margins recurved to near apex, smooth, 1- or 2-stratose; apices acute, rarely somewhat obtuse; costa usually long-excurrent as a spinulose-denticulate, usually decurrent awn, rarely percurrent, smooth; basal marginal cells quadrate or oblate, trigonous; distal laminal cells short-rectangular, occasionally isodiametric, 8–11 µm wide, strongly sinuose. |
Sexual condition | autoicous. |
autoicous. |
Capsule | dark red or brown, short-cylindric, 0.7–1.3 mm; exothecial cells usually quadrate, sometimes mixed with short-elongate or oblate cells, thin-walled, usually trigonous; stomata present; peristome patent or erect, often twisted, 350–600(–700) µm, red, densely papillose, usually perforated. |
light brown or red-brown, cylindric to elongate-cylindric, (0.8–)1–1.6 mm, sometimes striated; exothecial cells mostly irregularly shaped, mainly elongate, with numerous isodiametric and, sometimes, a few oblate cells, walls thin-walled to unevenly thickened and somewhat curved, usually trigonous; stomata present; peristome patent to squarrose, sometimes twisted, 300–430 µm, red or orange-red, densely papillose, entire or weakly perforated. |
Spores | 11–14(–19) µm, granulose or smooth. |
8–11 µm, nearly smooth. |
Schistidium apocarpum |
Schistidium robustum |
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Phenology | Capsules mature late spring to early summer. | Capsules mature late spring to early summer. |
Habitat | Rocks in somewhat shaded habitats | Dry to periodically moist calcareous rock |
Elevation | low to moderate elevations (0-1500 m) [low to moderate elevations (0-4900 ft)] | moderate to high elevations (400-2100 m) [moderate to high elevations (1300-6900 ft)] |
Distribution |
AK; MI; NY; VT; WA; WI; AB; BC; NB; NF; NS; ON; QC; Greenland; Eurasia
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ND; SD; WA; AB; BC; NF; NT; ON; QC; YT; Europe |
Discussion | Although H. H. Blom (1996) considered Schistidium apocarpum to be restricted in the flora area to the eastern portions of North America, it is more widespread and scattered across the continent. The denticulate leaf margins, papillose abaxial costal surface, short-cylindrical capsules, and the thin-walled, often evenly quadrate exothecial cells are distinguishing characters. The long peristome teeth are also useful in identifying S. apocarpum. In good condition the peristome can only be confused with that of S. trichodon, which differs in the darker, often black color of its plants, the peristome teeth often forming a dome, and the cylindrical capsules that retain the columella. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The long, spinulose-denticulate and decurrent awns, strongly sinuose laminal cells, and brown or red-brown, cylindrical capsules with primarily elongate exothecial cells are characteristic features of Schistidium robustum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 211. | FNA vol. 27, p. 222. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Grimmia apocarpa, S. lancifolium, S. umbrosum | Grimmia robusta |
Name authority | (Hedwig) Bruch & Schimper: Bryol. Europ. 3: 99. (1845) | (Nees & Hornschuch) H. H. Blom: Bryophyt. Biblioth. 49: 149. (1996) |
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