Dicranum condensatum
Dicranum elongatum
condensed dicranum moss
dense heron's-bill moss, elongate dicranum moss
1–9 cm, densely tomentose below with reddish brown rhizoids.
2–10 cm, tomentose throughout 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.
erect-spreading, erect-appressed to rarely spreading when dry, apex sometimes flexuose, smooth, (2.5–)3–4.5(–6) × 0.3–0.5 mm, from a lanceolate base to a long, fine, tubulose subula, apex usually acute, sometimes apical leaves of stems blunt, julaceous;
margins entire, rarely slightly denticulate at apex;
laminae 1-stratose;
costa percurrent or shortly excurrent, 1/6–1/4 the width of the leaves at base, smooth or weakly rough above on abaxial surface, abaxial ridges absent, with a row of guide cells, two stereid bands not extending to apex, adaxial and abaxial epidermal layers of cells usually not differentiated or sometimes a few cells in both layers enlarged;
cell walls between lamina cells slightly bulging;
leaf cells smooth;
alar cells 1-stratose or 2-stratose, well-differentiated, not extending to costa;
proximal laminal cells usually elongate, pitted, (14–)24–36(–49) × (2–)4–6(–9) µm;
distal laminal cells short-rectangular, quadrate, rounded, or sometimes irregularly shaped, incrassate, not pitted, (5–)12–17(–23) × (4–)6–8(–9) µm. Sexual condition dioicous;
male plants as large as females;
interior perichaetial leaves abruptly short-acuminate, convolute-sheathing.
1–4 cm, solitary, rarely 2 per perichaetium, yellowish.
1.5–2 cm., solitary, yellowish to yellowish 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.
1.2–1.8 mm, nearly straight and erect to slightly arcuate, striate when dry, yellowish brown;
operculum 1.2–1.8 mm.
19–26 µm.
17–22 µm.
Dicranum condensatum
Dicranum elongatum
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.)
Dicranum elongatum is easy to recognize because the plants are relatively small, slender, glossy, and grow in dense, compact tufts. The leaves are short, narrow, usually less than 6 × 0.5 mm, ending in a long, fine, tubulose subula, acute at the apex, smooth or nearly so on the abaxial surface, and have entire margins or rarely some denticulations at the apex. Capsules, which are not uncommon on plants in some arctic localities, are short, less than 2 mm, straight and erect to slightly arcuate, smooth but striate when dry.
Dicranum elongatum can readily be confused with the closely related D. groenlandicum. They both are arctic-alpine species sharing nearly the same type of habitat with almost the same distribution. They can usually be readily distinguished in their typical form but there appear to be many intergradations that cause difficulty. Dicranum groenlandicum has narrowly obtuse leaf apices and cells that are pitted to well above the middle of the leaf in contrast to the acute leaf apices and cells that are pitted only up to the middle of the leaf in D. elongatum. E. Hegewald (1972) found that the pits in the leaf are the most reliable means of separating difficult specimens of Finnish plants. H. A. Crum and L. E. Anderson (1981) expressed doubt as to whether the two are genetically different. Both D. elongatum and D. groenlandicum often bear at the apex of some stems julaceous shoots with small, ovate, broad leaves with obtuse apices. This can lead to the misidentification of some plants of D. elongatum unless the leaves in the basal part of the stems are always used to determine the shape of the leaf apices.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
LA Plants
MD Biodiversity
MI Flora
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
BC
MN Wildflowers
PNW Herbaria
