Sphagnum obtusum |
Sphagnum subfulvum |
|
---|---|---|
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 robust, usually soft and lax, sometimes moderately stiff, capitulum typically enlarged and flat-topped, ± stellate; green to golden brown, unshaded plants often reddish purple, plants with metallic sheen 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-lingulate to broadly lingulate, 0.9–1.3 mm, apex broadly rounded to obtusely angled, border very strong and broad at base (more than 0.4 width); hyaline cells rhombic, efibrillose, most 0–1-septate. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
long, tapering, imbricate, not 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, 2–2.5 mm, concave, straight, apex involute; hyaline cells on convex surface with elliptic pores along the commissures grading from moderate-sized pores near leaf apex to large pores at the base, concave surface with large round pores in proximal portions of leaf. |
Sexual condition | dioicous. |
monoicous. |
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. |
23–31 µm, irregularly coarsely papillose on both surfaces; proximal laesura less than or equal to 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 1–2 pendent branches. |
Sphagnum obtusum |
Sphagnum subfulvum |
|
Phenology | Capsules mature early summer. | |
Habitat | Forming carpets in minerotrophic peatlands | Minerotrophic and hygrophytic, forming hummocks in shrubby and wooded medium and rich 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; ME; MI; MN; NH; NJ; NY; VT; BC; NF; ON; QC; YT; Greenland; 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 of Sphagnum subfulvum are common. This species is associated with S. centrale, S. contortum, S. teres, and S. warnstorfii. Although it is normally more minerotrophic, S. subfulvum does occasionally (in Newfoundland) occur in the same mires as S. flavicomans. The latter lacks the metallic sheen of S. subfulvum and its stem leaves are not as narrow and acute. In some forms S. subfulvum may develop a purplish gloss that may lead to confusion with S. subnitens but the color of that species has a definite red component and its stem leaves are narrower and more sharply pointed than those of S. subfulvum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 98. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. nitidum | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | Sjörs: Svensk Bot. Tidskr. 38: 404. (1944) |
Web links |