Sphagnum obtusum |
Sphagnum bergianum |
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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, capitulum more or less flat-topped and large; dark brown overall with a golden center to the capitulum and a distinctive deep red tinge in the field which becomes a pinkish purple sheen upon drying. |
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 broadly triangular-lingulate, 1.15–1.25 × 0.8 mm, apex slightly to broadly obtuse, border moderately broadened at base; hyaline cells mostly 1-septate with a few to many 2-septate in the mid region, shape rhomboid. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
more or less 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. |
1.2–1.3 × 0.65–0.75 mm, broadly ovate, apex involute; hyaline cells on convex surface with numerous round to elliptic pores along the commissures, these grading from small pores at the apex to large pores at the base; concave surface aporose except for a few large pores in the lower side regions. |
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. |
26–30 µm. |
Branch | fascicles with 2 spreading and 2 pendent branches.; branch stems green, with cortex enlarged with conspicuous retort cells. |
fascicles with 2 spreading and 1 hanging branch. |
Sphagnum obtusum |
Sphagnum bergianum |
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Habitat | Forming carpets in minerotrophic peatlands | Hummocks in fens |
Elevation | low to moderate elevations | low to moderate elevations |
Distribution |
AK; MN; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland; Eurasia |
AK; NF |
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 bergianum forms dense hummocks in medium to rich fen habitats and is associated with such species as Sphagnum warnstorfii, S. subfulvum, S. subsecundum, S. platyphyllum and S. fuscum. Sphagnum bergianum is quite distinct in the field from its very dark brown color tinged with a deep red as well as its 5-ranked branch leaves. Sphagnum subnitens is colored a light brown and red combination, and has unranked branch leaves. Sphagnum subfulvum has a golden brown color that can be tinged with purple but also has unranked branch leaves. Sphagnum flavicomans is a similar-sized brown species of sect. Acutifolia that overlaps S. bergianum in Newfoundland but it is golden brown, lacks the red tinge and has a longer and narrower branch and stem leaves. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 90. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | R. E. Andrus: Sida 22: 964, figs. 14–20. (2006) |
Web links |