Dicranum majus
Dicranum pallidisetum
dicranum moss
dicranum moss, pale-stalk broom-moss, pale-stalk heron's-bill moss
3–16 cm, naked or with a few whitish rhizoids, rarely moderately tomentose, rhizoids (micronemata) in rows above each leaf.
1–6 cm, tomentose with white or reddish brown rhizoids.
somewhat sparse, falcate-secund or erect-patent, flexuose or straight, little changed when dry, usually smooth, (6–)8–11.5(–15) × 1–2 mm, concave proximally, tubulose above, from a lanceolate to ovate-lanceolate base, gradually narrowed to a long, falcate-secund or straight, acute apex;
margins serrate in the distal half, sometimes slightly serrulate above to almost entire;
laminae 1-stratose or with few 2-stratose regions on or near the margins;
costa percurrent to shortly excurrent, 1/12–1/7 the width of the leaves at base, toothed distally or serrulate to nearly smooth on abaxial surface, with a double row of guide cells that is sometimes interrupted, two stereid bands extending to apex, adaxial epidermal layer of cells with some cells differentiated, the abaxial layer completely differentiated;
cell walls between lamina cells not bulging;
leaf cells smooth or abaxially prorate or toothed above;
alar cells 2-stratose or multistratose, well-differentiated, not extending to costa;
proximal laminal cells elongate, pitted, (42–)71–112(–140) × (5–)9–10(–15) µm;
distal laminal cells shorter, linear to oval, pitted, (42–)47–61(–99) × (7–)10–11(–17) µm. Sexual condition pseudomonoicous;
dwarf males among rhizoids of female plants;
interior perichaetial leaves abruptly long-acuminate, convolute-sheathing.
often secund, straight or nearly so, often crisped when dry, smooth, 4–8 × 0.5–1 mm, lanceolate, acute, tubulose to apex;
margins entire below, serrulate ot serrate near apex;
laminae 1-stratose or sometimes 2-stratose on distal margins;
costa excurrent, 1/5–1/3 the width of the leaves at base, abaxially papillose or toothed from leaf middle to apex, abaxial ridges absent, with a row of guide cells, stereid bands often present and well-developed in proximal part of leaf, absent in distal 1/4–1/3 of leaf, cells above and below guide cells large and thin-walled;
cell walls between lamina cells not or slightly bulging;
leaf cells smooth or often strongly papillose in distal half of leaf;
alar cells 2-stratose, differentiated, often extending to costa, abaxial ridges absent;
proximal laminal cells linear to rectangular, with or without pits, (26–)58–95(–130) × (10–)12–14(–16) µm;
distal laminal cells quadrate, rounded, irregularly angled or short-rectangular, not pitted, (10–)15–26(–38) × (8–)9–11(–12) µm. Sexual condition dioicous;
male plants as large as female plants;
interior perichaetial leaves abruptly short-acuminate, convolute-sheathing.
2.5–5 cm, aggregate, 2–5 per perichaetium, rarely solitary, yellow to light brown.
1–2.5 cm, solitary or sometimes 2, rarely 3, per perichaetium, yellow, rarely reddish yellow or brown with age.
2–3.5 mm, arcuate, inclined to horizontal, smooth to faintly striate when dry, dark brown or yellowish brown;
operculum 2–3 mm.
1.5–3.5 mm, arcuate, inclined, often with a small struma, strongly furrowed when dry, contracted below mouth, yellow or yellowish brown, rarely reddish yellow or brown with age;
operculum 1.5–2.5 mm.
14–19 µm.
14–20 µm.
Dicranum majus
Dicranum pallidisetum
Varieties ca. 12 (2 in the flora).
Dicranum majus is the only North American species of the genus with a double row of guide cells. It is a distinctive species with oceanic tendencies and in North America it commonly grows in northern coastal localities on both sides of the continent, occasionally occurring inland in very moist habitats.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Dicranum pallidisetum has often been confused with D. fuscescens, being considered a form of it for many years (R. R. Ireland 1966). Unlike that species, which often occurs at low altitudes below 800 m, D. pallidisetum occurs predominately at high elevations, 800–2000 m, rarely being found as low as 500 m. It is distinguished from D. fuscescens by its tubulose leaves, usually 1-stratose or rarely 2-stratose on the margins, by its costa cross section that shows no stereid bands in the distal 1/3 of the leaf, and by its yellow or yellow-brown capsules that are sometimes 2–3 per perichaetium. In contrast, D. fuscescens has leaves keeled above, usually 2-stratose on both margins, rarely 1-stratose on one margin, stereid bands present throughout the leaf and dark brown to reddish brown capsules that are solitary or rarely 2 per perichaetium.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves falcate-secund, 8-15 mm; margins serrate in the distal half; costa toothed distally on abaxial surface, with a double row of guide cells. | var. majus |
1. Leaves erect-patent, 6-8 mm; margins slightly serrulate above to almost entire; costa serrulate to nearly smooth distally on abaxial surface, with an interrupted double row of guide cells | var. orthophyllum |
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