Dicranum condensatum
Dicranum ontariense
condensed dicranum moss
Ontario dicranum moss
1–9 cm, densely tomentose below with reddish brown rhizoids.
3–8 cm, densely tomentose below with reddish brown rhizoids.
erect-spreading, flexuose, ± curled at the tips when dry, slightly undulate or rugose, (2–)3.5–4.5(–7) × 0.5–1 mm, concave below, strongly keeled above, oblong-lanceolate, with a broad lanceolate base gradually narrowing to a short-acuminate apex;
margins serrulate in the distal half, involute in central part;
laminae 1-stratose, with a few 2-stratose regions;
costa percurrent to shortly excurrent, 1/10–1/5 the width of the leaves at base, strong, smooth or papillose to toothed above on abaxial surface, abaxial ridges absent, with a row of guide cells, two thick stereid bands extending well into the apex, adaxial epidermal layer of cells not differentiated, the abaxial layer differentiated;
cell walls between lamina cells strongly bulging;
leaf cells papillose above on abaxial surface, sometimes nearly smooth;
alar cells 2-stratose, differentiated, not extending to costa;
proximal laminal cells elongate, pitted, (25–)41–56(–112) × (5–)6–7(–10) µm, abruptly shorter towards the apex;
distal laminal cells quadrate, irregularly angled, rounded or rectangular, not or indistinctly pitted, cell walls unequally thickened, (5–)7–8(–20) × (5–)7–8(–12) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants;
interior perichaetial leaves abruptly short-acuminate, convolute-sheathing.
falcate-secund, flexuose, contorted when dry, slightly undulate, (5–)6.5–9(–10) mm × 1–1.5 mm, concave below, keeled above, from a lanceolate base to a long-acuminate apex;
margins plane, strongly serrate above;
laminae 1-stratose, rarely with 2-stratose regions on margins or near costa;
costa percurrent to slightly excurrent, 1/6–1/5 the width of the leaves at base, papillose to spinose above on numerous, low abaxial ridges, with a row of guide cells, two thick, well-developed stereid bands above and below extending to apex, adaxial epidermal layer of cells not differentiated, the abaxial layer differentiated;
cell walls between lamina cells not bulging or weakly bulging;
leaf cells prorate on abaxial surface, sometimes papillose adaxially;
alar cells 2-stratose, rarely 3-stratose in parts, differentiated, not extending to costa;
proximal laminal cells rectangular, pitted, (22–)40–64(–126) × (2–)7–8(–10) µm;
distal laminal cells short-rectangular to rectangular, not pitted, ± in longitudinal rows, marginal cells usually more elongate, some distal cells with long toothlike projections, scattered on abaxial surface, (7–)12–18(–42) × (5–)8–12(–16) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants;
interior perichaetial leaves abruptly long-acuminate, convolute-sheathing.
1–4 cm, solitary, rarely 2 per perichaetium, yellowish.
2–3.5 cm, often aggregate 2–5 per perichaetium, sometimes solitary, yellow, brown or reddish yellow.
1.5–3 mm, arcuate, inclined to horizontal, furrowed when dry, slightly contracted below the mouth, yellowish brown;
operculum 1.5–2.5 mm.
2–3 mm, arcuate, inclined to horizontal, furrowed when dry, yellow to light brown;
operculum 1.5–3 mm.
19–26 µm.
9–20 µm.
Dicranum condensatum
Dicranum ontariense
Dicranum condensatum is a common species recognized in the field by its occurrence on sandy soil, by its light green to yellowish brown, dull plants in compact, dense tufts, its erect-spreading, oblong-lanceolate leaves, narrowing to a short-acuminate apex, keeled above, somewhat undulate or rugose, curled at tips when dry, and its solitary setae with an arcuate, inclined to horizontal capsule. The papillose leaf cells with strongly bulging walls between the cells and the irregularly angled median and distal cells with nonpitted walls are distinctive microscopic characters. Dicranum spurium is the species most commonly confused with D. condensatum. Both species occur on sandy soil with their ranges overlapping. The former occurs farther northward, where it is found in Newfoundland, while the latter occurs farther to the south, where its range extends to the tip of Florida. Dicranum spurium has broader leaves, the broadest point near the middle rather than near the base like D. condensatum, and leaves that are tubulose above (most noticeable when wet) rather than keeled. Rarely, D. condensatum can be mistaken for 9. D. ontariense as discussed under that species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
W. L. Peterson (1979) recorded Dicranum ontariense from Alberta. This is a North American endemic species that was previously mistaken for D. drummondii Müller Hal., a predominately Eurasian species which was unknown on this continent until it was discovered just recently on the Aleutians Islands. Peterson (1977) clarified the taxonomic position of D. ontariense, while P. Isoviita (1977) amplified on the complex nomenclatural details of why it must be recognized as a species distinct from D. drummondii. The main distinguishing features of D. ontariense are the dark to light green, dull, falcate-secund, flexuose tipped, slightly undulate leaves, contorted when dry, keeled above from a lanceolate base to a long-acumination, the leaf apices papillose to spinose above on abaxial surface, the laminae 1-stratose except for occasional 2-stratose regions on margins, the leaf margins plane, strongly serrate above, and the usually multiple sporophytes, 2–5 per perichaetium.
This species is sometimes confused with an environmental form of Dicranum undulatum that has nearly percurrent costae and ± acute apices. The aggregate setae of D. ontariense will immediately distinguish it from that form, which has solitary setae. The dull leaves that are contorted when dry, and the leaf apices that are long-acuminate, abundantly spinose on the abaxial surface, are other superficial features to distinguish it from D. undulatum, which has shiny, usually broadly acute, smooth or serrulate leaf apices. Also, on occasion, D. ontariense can be confused with large forms of D. condensatum when sterile. The thin-walled, short-rectangular to quadrate distal-median cells in more or less regular rows of the former will distinguish it from the latter, which has irregularly shaped cells that are thick-walled and usually not in well defined rows. When fruiting, the aggregate setae on some of the plants of D. ontariense will immediately distinguish it from D. condensatum, which has solitary setae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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