Sphagnum obtusum |
Sphagnum recurvum |
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sphagnum |
recurved 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 to robust, moderately stiff-stemmed, ± lax, but not compact; green to pale yellow to yellowish brown; capitulum typically strongly convex in open grown forms, but flat and ± 5-radiate in shade forms. |
Stem | 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. |
pale green to yellowish; superficial cortex of 2 layers of enlarged, thin-walled and well differentiated cells.; stem leaves triangular, triangular-lingulate to lingulate, more than 0.8 mm, appressed, apex obtuse to broadly obtuse, erose to fimbriate; hyaline cells efibrillose and nonseptate. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
straight and often tapering, often 5-ranked, leaves not much elongate at distal end of branches. |
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-lanceolate, 1.4–2 mm, straight; slightly undulate and sharply recurved; margins entire; hyaline cells on convex surface with 1 pore per cell at cell apex, concave surface with round wall thinnings in the cell ends and angles; chlorophyllous cells triangular in transverse section and well-enclosed on concave surface. |
Sexual condition | dioicous. |
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. |
22–28 µm; papillose on both surfaces; proximal laesura more than 0.5 spore radius. |
Branch | fascicles with 2 spreading and 2 pendent branches.; branch stems green, with cortex enlarged with conspicuous retort cells. |
fascicles with 2 spreading and 2 pendent branches.; branch stems green, cortex enlarged with conspicuous retort cells. |
Sphagnum obtusum |
Sphagnum recurvum |
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Phenology | Capsules mature late summer to early fall. | |
Habitat | Forming carpets in minerotrophic peatlands | Forming carpets in a variety of very poor to poor fen habitats, including sedge fens, pocosins, bay swamps |
Elevation | low to moderate elevations | low to moderate elevations |
Distribution |
AK; MN; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland; Eurasia |
AL; AR; CT; DE; FL; GA; IL; IN; KY; LA; MA; MD; ME; MO; MS; NC; NH; NJ; NY; OH; PA; SC; TN; TX; VA; VT; WV; NF; NS; South America
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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 in Sphagnum recurvum are uncommon. This species is found exclusively in the New World. It has several strong characters that distinguish it from S. flexuosum, and the opinion of H. A. Crum (1997) that the two species are synonymous is rejected. See discussion under 30. S. flexuosum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 75. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. pentastichon, S. pulchricoma, S. riparioides | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | P. Beauvois: Prodr. Aethéogam., 88. (1805) |
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