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schistidium moss

schistidium moss, stook grimmia, stook schistidium

Habit Plants in open tufts or mats, olivaceous to brownish (black), sometimes with yellowish tones. Plants in open tufts or extensive mats, black, dark olivaceous, or brownish-olivaceous.
Stems

1.2–12 cm, central strand weak or absent.

1.8–12 cm, central strand weak or absent.

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.

usually somewhat curved, rarely secund, ovate-lanceolate, sharply keeled distally, 1.7–2.7 mm, 1-stratose;

margins usually recurved throughout and denticulate distally, 1-stratose or 2-stratose;

apices acute;

costa percurrent or excurrent as a short, denticulate, weakly decurrent awn, abaxial surface usually weakly papillose;

basal marginal cells quadrate or short-rectangular, sometimes trigonous;

distal laminal cells mostly short-rectangular, 8–10 µm wide, usually trigonous, 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.

red-brown, cylindric to short-cylindric, rarely cupulate, 0.7–1.2 mm, sometimes ribbed when dry;

columella persistent within capsule;

exothecial cells mainly isodiametric, sometimes mixed with short-elongate cells, thin-walled, trigonous;

stomata present;

peristome erect or ascending, often twisted inwards and overlapping distally, forming a dome, 400–700 µm, red, finely papillose, rarely with a few narrow slits.

Spores

11–14(–19) µm, granulose or smooth.

9–13(–19) µm, granulose or nearly smooth.

Schistidium apocarpum

Schistidium trichodon

Phenology Capsules mature late spring to early summer. Capsules mature late spring to early summer.
Habitat Rocks in somewhat shaded habitats Usually on calcareous rock (collected once on acidic rock in Washington State), open to shaded habitats
Elevation low to moderate elevations (0-1500 m) (low to moderate elevations (0-4900 ft)) low to high elevations (0-3500 m) (low to high elevations (0-11500 ft))
Distribution
from FNA
AK; MI; NY; VT; WA; WI; AB; BC; NB; NF; NS; ON; QC; Greenland; Eurasia
[WildflowerSearch map]
from FNA
AK; CO; MT; WA; BC; NB; NF; NS; NT; QC; YT; Eurasia
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 habitat, almost always on calcareous rock, its black or dark olivaceous color, the lack of long awns, the long, often domed peristome, and the persistence of the columella within the capsule make Schistidium trichodon a distinctive species.

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

Source FNA vol. 27, p. 211. FNA vol. 27, p. 225.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Schistidium Grimmiaceae > subfam. Grimmioideae > Schistidium
Sibling taxa
S. agassizii, S. atrichum, S. atrofuscum, S. boreale, S. cinclidodonteum, S. confertum, S. crassipilum, S. crassithecium, S. cryptocarpum, S. dupretii, S. flaccidum, S. flexipile, S. frigidum, S. frisvollianum, S. grandirete, S. heterophyllum, S. holmenianum, S. liliputanum, S. maritimum, S. occidentale, S. papillosum, S. pulchrum, S. rivulare, S. robustum, S. strictum, S. subjulaceum, S. tenerum, S. trichodon, S. venetum
S. agassizii, S. apocarpum, S. atrichum, S. atrofuscum, S. boreale, S. cinclidodonteum, S. confertum, S. crassipilum, S. crassithecium, S. cryptocarpum, S. dupretii, S. flaccidum, S. flexipile, S. frigidum, S. frisvollianum, S. grandirete, S. heterophyllum, S. holmenianum, S. liliputanum, S. maritimum, S. occidentale, S. papillosum, S. pulchrum, S. rivulare, S. robustum, S. strictum, S. subjulaceum, S. tenerum, S. venetum
Synonyms Grimmia apocarpa, S. lancifolium, S. umbrosum Grimmia trichodon
Name authority (Hedwig) Bruch & Schimper: Bryol. Europ. 3: 99. (1845) (Bridel) Poelt: Svensk Bot. Tidskr. 47: 253. (1953)
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