Pohlia nutans |
Pohlia atropurpurea |
|
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nodding pohlia, nodding thread-moss, pohlia moss |
pohlia moss |
|
Habit | Plants small to large, green or rarely reddish, dull. | Plants very small, green to reddish, shiny. |
Stems | 0.5–3.5(–10) cm. |
0.2–0.4 cm. |
Leaves | 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. |
erect-spreading to spreading, lanceolate, 0.6–1.2 mm; base not or scarcely decurrent; margins weakly serrulate in distal 1/3; costa ending well before apex; distal medial laminal cells laxly and broadly rhomboidal, 65–110 × 10–12 µm, walls thin. |
Seta | orange to orange-brown. |
orange-brown. |
Sexual condition | paroicous, rarely dioicous; perigonial leaves ovate-lanceolate; perichaetial leaves somewhat differentiated, ± long-lanceolate. |
dioicous; perigonial leaves to 3 mm; perichaetial leaves scarcely differentiated, lanceolate. |
Capsule | 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 superficial; annulus absent; operculum short- to long-conic; exostome teeth dark brown to red-brown, triangular-acute; endostome yellow to yellow-brown, basal membrane 1/2 exostome length, segments tapered apically, distinctly keeled, broadly perforate, cilia long, nodulose. |
Spores | 16–22 µm, finely to distinctly roughened. |
15–21 µm, finely roughened. |
Specialized | asexual reproduction typically absent. |
asexual reproduction absent. |
Pohlia nutans |
Pohlia atropurpurea |
|
Phenology | Capsules mature spring (Apr–Jun). | Capsules mature spring (Apr–Jun). |
Habitat | Soil banks, logs, tree bases, disturbed places | Disturbed clay or rarely sandy soil, path banks, along streams |
Elevation | low to high elevations | low elevations |
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Africa; Greenland; Eurasia; Mexico (Nuevo León); Australia
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AK; CA; IA; ID; MN; NY; WA; BC; MB; NL; ON; YT; Europe |
Discussion | 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 atropurpurea has sporophytes similar to those of P. melanodon, with dark reddish brown exostome teeth, yellow endostomes, and immersed stomata. This uncommon northern species is very small and soft, generally consisting of unbranched gametophytes that do not form extensive cushions. As in P. melanodon, the laminal cells are lax and thin-walled. Genetic relationships between this species and P. melanodon need study; P. atropurpurea could be a northern form of that species. Medial laminal cells of the perichaetial leaves are narrower than the broadly lax cells of proximal stem leaves. The exothecial cell walls of capsules of this species are somewhat collenchymatous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 28, p. 196. | FNA vol. 28, p. 211. |
Parent taxa | Mielichhoferiaceae > Pohlia | Mielichhoferiaceae > Pohlia |
Sibling taxa | ||
Synonyms | Webera nutans, P. sphagnicola | Bryum pulchellum var. atropurpureum |
Name authority | (Hedwig) Lindberg: Musc. Scand., 18. (1879) | (Wahlenberg) H. Lindberg: Acta Soc. Fauna Fl. Fenn. 16(5): 14. (1899) |
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