Sphagnum obtusum |
Sphagnum quinquefarium |
|
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sphagnum |
five-rank peat-moss, sphagnum |
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Habit | Plants moderate to robust, weak-stemmed, yellow, yellowish brown to golden brown; capitulum varying from rounded, not 5-radiate and twisted to flat 5-radiate and straight branched. | Plants moderate-sized, typically stiff and compact, capitulum usually hemispherical; green, grayish white, pale yellow, purplish red, may have a slight metallic luster when dry. |
Stem(s) | pale green to pale brown; superficial cortex of weakly to moderately differentiated.; stem leaves triangular-lingulate, 0.9–1.3 mm; usually appressed; apex obtuse and often erose; hyaline cells efibrillose and nonseptate. |
leaves triangular to triangular-lingulate, 1–1.3 mm, apex acute to slightly obtuse, border broad at base (more than 0.25 width); hyaline cells narrowly rhomboid, mostly 0–1-septate and mostly efibrillose. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
usually strongly 5-ranked. |
Branch leaves | ovate to ovate-lanceolate; more than 1.8 mm; straight, stiff, not much undulate and reflexed to recurved; margins entire; hyaline cells on convex surface with a few end pores, but mostly numerous small to very small (often barely visible) pores or wall thinnings free from the commissures, on concave surface similar, but with pores generally fewer and larger; chlorophyllous cells triangular in transverse section, just reaching concave surface or slightly enclosed. |
ovate to ovate-lanceolate, 1.1–1.5 mm, concave, straight, apex slightly involute; hyaline cells on convex surface with numerous oval to elliptic pores along commissures grading from small pores near apex to large round pores at base, concave surface with large round pores in proximal portions of leaf. |
Sexual condition | dioicous. |
monoicous or dioicous. |
Spores | 18–27 µm; both surfaces covered with rough, irregular verrucate plates of papillae, bifurcated Y-mark sculpture on distal surface; proximal laesura less than 0.5 spore radius. |
19–27 µm, finely papillose on proximal surface, pusticulate on distal surface; proximal laesura less than 0.4 spore radius. |
Branch | fascicles with 2 spreading and 2 pendent branches.; branch stems green, with cortex enlarged with conspicuous retort cells. |
fascicles with mostly 3 spreading and 1–2 pendent branches. |
Sphagnum obtusum |
Sphagnum quinquefarium |
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Phenology | Capsules mature mid summer. | |
Habitat | Forming carpets in minerotrophic peatlands | Weakly minerotrophic and hygrophytic, wet mineral bedrock, damp coniferous humus along coast and in montane regions |
Elevation | low to moderate elevations | low to high elevations |
Distribution |
AK; MN; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland; Eurasia |
AK; CT; GA; MA; MD; ME; MN; NC; NH; NY; PA; TN; VA; VT; WV; BC; MB; NB; NF; NS; ON; QC; Eurasia |
Discussion | Sporophytes are uncommon in Sphagnum obtusum. This is a quite phenotypically variable species that warrants further investigation, which may result in taxonomic splitting. The strongly obtuse stem leaf should separate it from any similar species with which it occurs. Sphagnum mendocinum looks similar phenotypically but there appears to be no range overlap with S. obtusum. The tiny branch leaf pores, which may seem like no more than pinpricks in the cell surface, easily separate S. obtusum microscopically from other species of sect. Cuspidata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Sporophytes are common in Sphagnum quinquefarium. This species is usually associated with S. capillifolium, S. girgensohnii, and S. russowii. No other species of sect. Acutifolia has the combination of quinquefarious branch leaves and three spreading branches per fascicle. Sphagnum rubiginosum has three spreading branches but the branch leaves are quite unranked and its lingulate stem leaf is quite distinct from the triangular stem leaf of S. quinquefarium. See also discussion under 86. S. talbotianum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 96. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. acutifolium var. quinquefarium, S. schofieldii | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | (Lindberg) Warnstorf: Hedwigia 25: 222. (1886) |
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