Dicranum condensatum
Dicranum brevifolium
condensed dicranum moss
shortleaf dicranum moss
1–9 cm, densely tomentose below with reddish brown rhizoids.
2–8 cm, densely tomentose with brown to orange rhizoids nearly to stem apex.
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 to erect-spreading, often at wide angles from stems, strongly crisped when dry, often with a few undulations in the distal half, (3–)5.5–6.5(–8.5) × 0.4–0.8 mm, concave below, keeled above, lanceolate, acute;
margins entire below, serrulate above, incurved in the middle of the leaf;
laminae 1-stratose or with 2-stratose regions in distal half of leaf, especially on margins, sometimes with entire laminae 2-stratose, rarely margins 3-stratose;
costa percurrent or shortly excurrent, 1/6–1/4 the width of the leaves at base, very prominent and rounded on abaxial surface, smooth or slightly rough above on abaxial surface, abaxial ridges absent, shaped like a pair of tongs, with one row of guide cells, 2 well-developed and thick stereid bands extending to the apex, adaxial epidermal layer of cells not differentiated, the abaxial layer differentiated;
cell walls between lamina cells strongly bulging;
leaf cells smooth to papillose above on abaxial surface;
alar cells 2-stratose, differentiated, sometimes extending to costa;
proximal laminal cells elongate-rectangular, pitted or not pitted, (15–)31–46(–75) × (5–)7–9(–12) µm;
distal laminal cells short, irregularly quadrate-rectangular, not pitted, (5–)7–14(–37) × (4–)8–9(–13) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants;
interior perichaetial leaves abruptly short-acuminate, convolute-sheathing.
1–4 cm, solitary, rarely 2 per perichaetium, yellowish.
1.3–3.5 cm, solitary, yellowish to brown.
1.5–3 mm, arcuate, inclined to horizontal, furrowed when dry, slightly contracted below the mouth, yellowish brown;
operculum 1.5–2.5 mm.
2–4 mm, long-cylindric, arcuate, inclined to horizontal, not or slightly strumose, striate to furrowed when dry, yellowish brown to dark brown;
operculum 1–2.5 mm.
19–26 µm.
14–30 µm.
Dicranum condensatum
Dicranum brevifolium
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.)
The distinctive leaves of Dicranum brevifolium are 4–8 mm, acute, often weakly undulate in the distal part, crisped when dry, standing out from the stems often at wide angles, concave proximally, and keeled distally, the laminae are often 2-stratose above, especially on margins and near costa, sometimes entirely 2-stratose with 3-stratose margins (sometimes apparent on plants at relatively high altitudes in the mountains in Alberta), and the costa is excurrent, very prominent and conspicuously rounded, especially noticeable below the leaf middle. The leaves in cross section are very distinctive, being shaped like a pair of tongs; abaxial epidermal layer of costal cells is differentiated but no adaxial epidermal layer cells are enlarged, and the cell walls between the lamina cells are almost always strongly bulging. Dicranum brevifolium has commonly been confused with three other species, D. muehlenbeckii, D. acutifolium, and D. fuscescens. Dicranum muehlenbeckii has only 1-stratose leaf laminae and the costae are much less prominent on the abaxial leaf surface than those of D. brevifolium. A cross section of the distal half of the leaves of D. muehlenbeckii shows a tubular outline with the cell walls between the lamina cells smooth and adaxial epidermal layer of costal cells differentiated, while the leaves of D. brevifolium are tong-shaped in outline with the cell walls between lamina cells strongly bulging and the adaxial epidermal layer of costal cells undifferentiated. Dicranum acutifolium differs from D. brevifolium by its erect-spreading to slightly curled leaves when dry, instead of crisped leaves standing out from the stems at wide angles, its costae that are usually moderately distinct and sometimes nearly flat on the abaxial surface, instead of being prominent and conspicuously rounded, its V-shaped leaves in cross section, instead of tong-shaped leaves, and its shorter capsules, 2–2.7 mm, compared to 2–4 mm. Dicranum fuscescens differs from D. brevifolium by its much less prominent costae on the abaxial leaf surface, by its V-shaped leaves in cross section, instead of tong-shaped leaves, and by its weakly bulging cell walls as seen in cross section.
The 2- or occasionally 3-stratose leaf laminae are unusual in the genus Dicranum. The only other species in North America with laminae often completely 2-stratose in the distal half is D. fulvum. No 3-stratose leaf laminae have been seen in that species, however. A recently described species in section Dicranum (where D. scoparium belongs) D. crassifolium C. Sérgio, R. Ochyra & A. Séneca, from Portugal, Spain, and Italy, has 2–3-stratose leaves. It is very unusual for a species in the type section to have anything but 1-stratose leaves.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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