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FNA | Family List | FNA Vol. 27 | Dicranaceae | Dicranum

11. Dicranum condensatum Hedwig, Sp.. Musc. Frond. 139. 1801.

Dicranum sabuletorum Renauld & Cardot

Plants in ± dense tufts, light green to yellowish brown, dull. Stems 1-9 cm, densely tomentose below with reddish brown rhizoids. Leaves 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. Seta 1-4 cm, solitary, rarely 2 per perichaetium, yellowish. Capsule 1.5-3 mm, arcuate, inclined to horizontal, furrowed when dry, slightly contracted below the mouth, yellowish brown; operculum 1.5-2.5 mm. Spores 19-26 µm.

Capsules mature spring. Exposed sandy soil, often in pine woods, frequently over sandstone and limestone; 0-700 m; N.B., N.S., Que.; Ala., Ark., Del., D.C., Fla., Ga., Ill., Ind., Kans., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va.

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.


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