Pohlia wahlenbergii
Pohlia ludwigii
pale nodding-cap moss, pale pohlia, Wahlenberg's pohlia moss
ludwig's pohlia moss, ludwig's thread-moss
0.8–10 cm.
0.8–3.5 cm.
laxly spreading to more stiffly erect, lanceolate to ovate-lanceolate, 0.6–1.2 mm;
margins weakly to strongly serrulate in distal 1/3;
costa ending well before apex;
distal medial laminal cells laxly and broadly hexagonal to rhomboidal, 65–110 µm, walls thin.
erect to ± spreading, lanceolate to broadly lanceolate, 1.2–2.4 mm;
base long-decurrent;
margins serrulate to serrate in distal 1/3;
costa subpercurrent;
distal medial laminal cells rhombic to rhomboidal, 40–80 µm, walls firm to thin.
orange-brown.
orange-brown.
dioicous;
perigonial leaves ovate;
perichaetial leaves weakly differentiated, lanceolate.
dioicous;
perigonial leaves broadly short-ovate;
perichaetial leaves scarcely differentiated, broadly lanceolate.
inclined ± 180°, brown to red-brown, sometimes stramineous, short-pyriform to urceolate, neck less than 1/3 urn length;
exothecial cells isodiametric, walls sinuate;
stomata immersed;
annulus absent;
operculum short- to long-conic;
exostome teeth light brown to red-brown, triangular-acute;
endostome hyaline to yellow, basal membrane 1/2 exostome length or slightly longer, segments tapered apically, distinctly keeled, broadly perforate, cilia long, nodulose.
inclined 90–180°, brown to stramineous, broadly pyriform, neck 1/3 urn length;
exothecial cells short-rectangular, walls weakly to moderately sinuate;
stomata superficial;
annulus present;
operculum bluntly conic;
exostome teeth yellow to brown, triangular-acute;
endostome hyaline, basal membrane to 1/2 exostome length, segments tapered apically, distinctly keeled, broadly perforate, cilia short to long.
15–21 µm, finely roughened.
14–21 µm, finely roughened.
asexual reproduction absent.
asexual reproduction absent.
Pohlia wahlenbergii
Pohlia ludwigii
Pohlia wahlenbergii is one of the most geographically widespread and common species of the genus. The leaves are pale whitish, decurrent, and have lax, thin-walled cells. The species varies greatly in size from very slender delicate plants in suboptimal habitats to large and deep cushions in cold high altitude and latitude sites. Large plants of P. wahlenbergii typically have red stems and sometimes reddish pigmentation to the leaves as well. Some authors refer large expressions to var. glaciale (or P. glaciale), but gradation in size and pigmentation is completely continuous, and different collectors draw the line between the typical variety and var. glaciale at different points. The exothecial cell walls in capsules of this species are somewhat collenchymatous.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Pohlia ludwigii is a rare alpine species, often found in habitats similar to those of P. obtusifolia and characterized by strongly decurrent leaves that are often slightly cucullate apically. The older lower leaves generally have a pink to reddish tinge. The leaf apices are acute to bluntly acute; the endostome segments are papillose; and the perichaetial leaf costae are very strong at their bases. In late snowmelt areas, P. ludwigii can form deep cushions when sterile.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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