Schistidium apocarpum
Schistidium holmenianum
schistidium moss
1.2–12 cm, central strand weak or absent.
2–13 cm, central strand absent.
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.
curved or erect when dry, narrowly ovate-lanceolate, usually sharply keeled distally, 1.6–2.8 mm, 1-stratose distally, sometimes with 2-stratose striae near costa proximally;
margins recurved to just before the apex, often less recurved or nearly plane on one side of leaf, smooth or slightly denticulate near apex, 1-stratose or 2-stratose;
apices acute;
costa percurrent or excurrent as a smooth or weakly denticulate awn, abaxial surface smooth or weakly papillose;
basal marginal cells quadrate or short-rectangular;
distal cells mostly short-rectangular, 7–9 wide, smooth, usually sinuose, walls usually orange-brown.
autoicous.
dioicous.
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.
dark brown, short-cylindric or cupulate, 0.6–0.9 mm;
exothecial cells isodiametric, quadrate, often irregularly angular, or elongate, cell walls thin, trigonous;
stomata present;
peristome patent, 275–440 µm, orange-red, usually densely papillose and strongly perforated.
11–14(–19) µm, granulose or smooth.
14–25 µm, verruculose.
Schistidium apocarpum
Schistidium holmenianum
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.)
Schistidium holmenianum does not grow on rock, but rather forms large tufts or mats over soil, or amongst litter and plants in arctic habitats. Schistidium grandirete grows in similar habitats but also on rock. The presence of sporophytes, the lighter color of the plants, the absence of orange-brown cell wall coloration, a more papillose costa, and the consistently larger cells separate S. grandirete from S. holmenianum. Although reported from North America, S. andreaeopsis (Müller Hal.) Lazarenko has been omitted in this treatment. All specimens that were examined, including those named as S. andreaeopsis, fall into the descriptions of S. holmenianum as provided by Steere and Brassard and H. H. Blom (1998). According to Blom, S. andreaeopsis has larger and more sinuose distal laminal cells, darker red-orange cell walls, a much weaker costa, and predominantly 1-stratose and denticulate or papillose-denticulate leaf margins.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Flora NW
MI Flora
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WildflowerSearch
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USDA Plants Database
