Sphagnum obtusum |
Sphagnum trinitense |
|
---|---|---|
sphagnum |
Trinity 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, slender and weak-stemmed, green to pale yellow; flaccid and plumose in aquatic forms to more compact and sprawling in emergent forms; green to pale yellow; capitulum not especially enlarged and differentiated. |
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 ovate-triangular to triangular, 1–1.6 mm; appressed to spreading; apex acute to slightly obtuse; hyaline cells often fibrillose and often 1-septate. |
Branches | tapering or in more robust forms, frequently blunt, straight to arcuate, leaves slightly to moderately elongated at distal end. |
straight and unranked, in capitulum tapering at distal end to a point, leaves greatly elongated 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. |
ovate-lanceolate to lanceolate, 2–3.5 mm; straight, undulate and slightly recurved when dry; margin serrulate; hyaline cells on convex surface with 0–1 small pores at cell apex on concave surface with round wall thinnings in cell angles (often indistinct or lacking); chlorophyllous cells trapezoidal in transverse section and exposed more broadly on the convex surface. |
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. |
26–40 µm; ± roughly to densely granulose. |
Branch | fascicles with 2 spreading and 2 pendent branches.; branch stems green, with cortex enlarged with conspicuous retort cells. |
stems green, cortex enlarged with conspicuous retort cells. |
Sphagnum obtusum |
Sphagnum trinitense |
|
Phenology | Capsules mature early to mid summer. | |
Habitat | Forming carpets in minerotrophic peatlands | Submersed or stranded at edge of shallow, acidic pond, lakes, and roadside ditches, mostly in sandy areas of the Atlantic coastal plain |
Elevation | low to moderate elevations | low to moderate elevations |
Distribution |
AK; MN; AB; BC; MB; NF; NT; NU; ON; QC; SK; YT; Greenland; Eurasia |
DE; FL; GA; IL; KS; LA; MA; MD; NC; NJ; NY; PA; SC; VA; South America |
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 are common in Sphagnum trinitense, which can often be distinguished from S. cuspidatum in the field by the appearance of its branches when wet. In this state the branches of S. trinitense just below the capitulum resemble a fine paintbrush drawn out to a pointed tip. See also discussion under 29. S. fitzgeraldii and 39. S. mississippiense. Spore features are taken from H. A. Crum (1984). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 73. | FNA vol. 27, p. 77. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. cuspidatum var. serratum, S. cuspidatum var. serrulatum, S. helleri, S. laxifolium var. serrulatum, S. serratum | |
Name authority | Warnstorf: Bot. Zeitung (Berlin) 35: 478. (1877) | Müller Hal.: Syn. Musc. Frond. 1: 102. (1848) |
Web links |