Sphagnum steerei |
Sphagnum arcticum |
|
---|---|---|
steere's sphagnum |
arctic sphagnum |
|
Habit | Plants moderate-sized to large, compact and stiff-stemmed with upswept branches; dark green and brown, dark chesnut brown, brown to blackish brown, often with bluish tinge when dry; forming dense low to moderately tall hummocks. | Plants moderately robust, capitulum distinct and flat-topped; golden brown, brown or dark-brown, less commonly variegated green and brown, without metallic luster when dry. |
Stem(s) | leaves to 1.2 × 0.8 mm; rarely hemiisophyllous; hyaline cells mostly nonseptate, comb-lamellae usually absent, but sometimes weak. |
leaves narrowly to broadly lingulate or sometimes lingulate-spatulate, (1.1–)1.2–1.4(–1.6) mm; apex broadly obtuse to obtuse-truncate and more or less fimbriate-lacerately resorbed, border in distal half narrow and often indistinct, in proximal half widened and filling up 1/3–1/2(–2/3) of the breadth at the base; hyaline cells broadly S-shaped to rhombic S-shaped, predominantly nonseptate but a few cells are 1–3-septate; efibrillose. |
Branches | short and blunt-tipped, leaves spreading. |
unranked, terete. |
Branch leaves | ovate to ovate-elliptical, 1.6–2.2 × 1 mm; hyaline cells on proximal half of convex surface with round to elliptic pores along the commissures; comb-lamellae on hyaline cell wall where overlying chlorophyllous cells; chlorophyllous cells broadly triangular in transverse section and well-enclosed on convex surface, end wall not thickened. |
broadly lanceolate to ovate-lanceolate, (1.1–)1.4–1.8(–2.1) mm, slightly concave, straight to slightly subsecund; apex involute; border entire; hyaline cells on convex surface with (5–)8–10(–12) semicircular to elliptical, ringed pores along the commissures, concave surface aporose or infrequently with 1–2 pores per cell in the distal portion of the cell, more numerous along leaf margins. |
Sexual condition | dioicous. |
unknown. |
Capsule | unknown. |
|
Spores | unknown. |
not seen. |
Branch | fascicles with 2 spreading and 1 pendent branch.; branch stems with hyaline cells non-ornamented, no or weak funnel-like projections on the end walls of cortical cells, cortical cell walls usually with large round pores. |
fascicles with 2 spreading and 1 pendent branch. |
Sphagnum steerei |
Sphagnum arcticum |
|
Habitat | Commonly in firm-bottomed poor to medium fen vegetation, subarctic to arctic regions | Forming low hummocks in weakly to moderately minerotrophic fens |
Elevation | low to moderate elevations | low to moderate elevations |
Distribution |
AK; MB; NT; NU; QC; YT; e Asia |
AK; QC; YT; Eurasia |
Discussion | Sphagnum steerei is usually easily recognized in the field by its dense growth habit and dark brown color. Its ecology is somewhat unclear due to taxonomic confusion with S. imbricatum in the strict sense and S. austinii (R. E. Andrus 1987). The latter is the only species in the imbricatum complex that occurs where S. steerei does. Contrary to the view of H. A. Crum (1997), S. steerei is quite distinct from S. affine and S. austinii. There is no range overlap with either of those species and the macroscopic appearance is also quite different. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Sporophytes are uncommon in Sphagnum arcticum. All collections of this fairly common species have been made north of 59° N latitude in wet or moist tundra vegetation. In its typical dark brown color, this species is often quite distinctive in the field. Sphagnum fuscum is smaller, not as dark, and its stem leaves are not as truncate-lacerate. Sphagnum subfulvum has a glossy sheen, which S. arcticum lacks, and its stem leaf has an obtuse but not lacerate apex. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 54. | FNA vol. 27, p. 89. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | S. imbricatum var. arcticum | |
Name authority | R. E. Andrus: Bryologist 90: 218. (1987) | K. I. Flatberg & Frisvoll: Bryologist 87: 143, figs. 1–22. (1984) |
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