Pohlia nutans
Pohlia wahlenbergii
nodding pohlia, nodding thread-moss, pohlia moss
pale nodding-cap moss, pale pohlia, Wahlenberg's pohlia moss
0.5–3.5(–10) cm.
0.8–10 cm.
erect to ± spreading, lanceolate to ovate-lanceolate, 2 mm;
base not or scarcely decurrent;
margins subentire or more often serrulate to serrate in distal 1/3;
costa subpercurrent, percurrent, or rarely short-excurrent;
distal medial laminal cells hexagonal to rhomboidal, firm, 50–90 µm, walls moderately thick.
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.
orange to orange-brown.
orange-brown.
paroicous, rarely dioicous;
perigonial leaves ovate-lanceolate;
perichaetial leaves somewhat differentiated, ± long-lanceolate.
dioicous;
perigonial leaves ovate;
perichaetial leaves weakly differentiated, lanceolate.
inclined 80–100°, orange to orange-brown, slender-pyriform, neck 1/2 urn length;
exothecial cells elongate-rectangular, walls straight;
stomata superficial;
annulus present;
operculum conic;
exostome teeth yellow to orange-brown, acute-triangular;
endostome hyaline or rarely orange-brown, basal membrane 1/2 exostome length, segments tapered apically, broadly keeled, broadly perforate, cilia short to long.
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.
16–22 µm, finely to distinctly roughened.
15–21 µm, finely roughened.
asexual reproduction typically absent.
asexual reproduction absent.
Pohlia nutans
Pohlia wahlenbergii
Pohlia nutans is the most common species of Pohlia in North America, Europe, and elsewhere in the Northern Hemisphere. In contrast to the treatment by A. J. Shaw (1982), P. sphagnicola is not separated here from P. nutans; the type of P. sphagnicola is European. Plants referable to P. sphagnicola, including North American collections, differ in being dioicous and having entire leaves, slightly shorter laminal cells, and smaller spores. The habitat in Sphagnum hummocks is not diagnostic; at least 80% of plants growing in Sphagnum are P. nutans. Pohlia schimperi, a northern form with reddish leaves, also dioicous, is not recognized, as per Shaw.
The peristome of Pohlia nutans is as well developed as any in Pohlia, with long, tapered, trabeculate exostome teeth and well-developed endostomes with broadly keeled, widely perforate segments and short to long cilia. The laminal cells are short- to elongate-hexagonal with thickened walls. The only other North American species with relatively thick-walled laminal cells is P. elongata; the cells of P. elongata are typically longer, but there is extensive overlap in sizes. Plants without sporophytes have generally been named P. nutans, although some collections from montane regions may actually be P. elongata; sporophytes of P. elongata have longer necks, as long as or longer than the urns, and reduced peristomes with endostome segments narrowly split along the keel and (usually) no cilia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
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- Local floras: BC
- Local Web sites: CalFlora, CalPhotos, Flora NW, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
