Sphagnum obtusum |
Sphagnum carolinianum |
|
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sphagnum |
Carolina 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 to large, erect to floating, green to dark brown; capitulum large, well defined and flat-topped. |
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 lingulate to lingulate-triangular, 0.7–1.5 mm (to 3 mm in isophyllous forms), apex erose; hyaline cells mostly 1–septate but in a few cells with 2–3 parallel septations, efibrillose to fibrillose throughout, pores present in hemiisophyllous and isophyllous forms. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
straight to somewhat curved, with spreading leaves. |
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. |
variable, broadly ovate to ovate-lanceolate, 1.3–5 mm; straight, hyaline cells on the convex surface with 4–8 µm round to elliptic pores in nearly continuous rows along the commissures, the concave surface aporose or with some porosity as on the convex surface. |
Sexual condition | dioicous. |
unknown. |
Capsule | not seen. |
|
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. |
not seen. |
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 in emergent forms, these reduced in aquatic forms to 2 per fascicle. |
Sphagnum obtusum |
Sphagnum carolinianum |
|
Habitat | Forming carpets in minerotrophic peatlands | Forming wet often floating carpets in pools in weakly minerotrophic mires |
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; DE; FL; GA; LA; MA; ME; MO; MS; NC; NJ; NY; SC; TN; TX; VA; 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.) |
The sporophytes of Sphagnum carolinianum are unknown. In its apparent restriction to the coastal plain, this species is most similar distributionally to such species as S. macrophyllum, S. fitzgeraldii, and S. tenerum. When forming carpets, S. carolinianum macrospically most resembles S. atlanticum but its branch leaves are not as elongate as those of the latter and its stem leaves have a much more obtuse apex. When growing aquatically, S. caroliniaum can resemble S. cribrosum, but in the latter species the hanging branches are not different from the spreading branches and may even be lacking. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 79. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. subsecundum var. carolinianum | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | R. E. Andrus: Bryologist 86: 257, figs. (1983) |
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