Sphagnum obtusum |
Sphagnum portoricense |
|
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sphagnum |
puerto rico sphagnum |
|
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 often quite robust, ± weak-stemmed, lax; green, bluish green, green and brown to dark golden brown, often speckled in appearance; found submerged in shallow water, stranded along shore lines in loose carpets. |
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 1.1 × 1 mm; rarely hemiisophyllous; hyaline cells non-ornamented, frequently septate. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
clavate and rounded at distal end. |
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. |
broadly ovate, 2.4 × 1.7 mm; hyaline cells on convex surface with numerous round pores along the commissures, comb-lamellae on hyaline cell walls where overlying chlorophyllous cells; chlorophyllous cells broadly triangular in transverse section and well-enclosed on the convex surface. |
Sexual condition | dioicous. |
dioicous. |
Capsule | with pseudostomata. |
|
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. |
22–29 µm; finely papillose on both surfaces; indistinct triradiate ridge on distal surface; proximal laesura 0.5–0.6 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 with hyaline cell comb-lamellae visible on interior cortex wall, cortical cell end walls with conspicuous funnel projections more than 1/2 length of cell, superficial cortical wall aporose. |
Sphagnum obtusum |
Sphagnum portoricense |
|
Habitat | Forming carpets in minerotrophic peatlands | Stream channels, shallow ponds, coniferous and hardwood swamps and pocosins |
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; FL; LA; NC; NJ; NY; SC; TX; Mexico; South America; West Indies |
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.) |
Sphagnum portoricense is normally very easily distinguished because of its wet growing habit and strongly clavate branches. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 54. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. sullivantianum | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | Hampe: Linnaea 25: 359. (1852) |
Web links |