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common brown peat-moss, rusty bogmoss, rusty peat moss, sphagnum

Habit Plants small and slender, stiff and usually compact, capitulum small and flat-topped; typically deep reddish brown, also greenish brown in shaded habitats and in early seasonal growth, without metallic lustre when dry. Plants small to moderate-sized, rarely robust, with distinct capitulum; green, brown, pink, red.
Stem(s)

leaves lingulate, 0.8–1.3 mm;

apex broadly rounded and entire to lacerate, sometimes slightly mucronate or slightly denticulate;

hyaline cells rhombic, 0–1(–2)-septate, usually efibrillose.

leaves similar in size to branch leaves; varying from triangular to lingulate-spatulate;

apex varying from acute and entire to very broad and lacerate;

border entire or, in one case, fimbriate;

hyaline cells rhomboid to S-shaped, non-ornamented, efibrillose or fibrillose, aporose or in hemiisophyllous forms porose, 0–2-septate, mostly resorbed on interior surface and mostly entire on exterior surface.

Branches

long and slender to short and compact, unranked to 5-ranked.

dimorphic, spreading branches usually longer and thicker than pendent branches.

Branch leaves

ovate-lanceolate, 1.1–1.3 mm, straight, concave, apex strongly involute;

margins entire, hyaline cells on convex surface with round to elliptic pores along the commissures, grading from small pores near the leaf apex to large pores near the base, concave surface with large round pores in proximal marginal regions of leaf.

ovate to ovate-lanceolate, margins entire or, in one case, toothed, involute near smooth apex;

hyaline cells efibrillose, non-ornamented, with round to elliptic pores along commissures on convex surface, fewer, larger and round mostly free pores on concave surface; chlorophyllous cells triangular to trapezoidal in transverse section, more broadly exposed on concave surface, end walls not thickened.

Sexual condition

dioicous.

usually dioicous, occasionally monoicous.

Capsule

equal to or less than 2 mm, with few to many pseudostomata.

Spores

17–30 µm, finely papillose on proximal surface and pusticulate on distal surface;

proximal laesura less than 0.5 spore radius.

typically less than 30 µm, coarsely to finely papillose on both surfaces, may have raised surface sculpture on distal surface;

proximal laesura typically less than or equal to 0.5 spore radius.

Branch

fascicles with 2 spreading and 1–2 pendent branches.

fascicles with 2(–3) spreading and 1–2 pendent branches.;

branch stems green, surrounded by 1 layer of efibrillose, non-ornamented, inflated, thin-walled hyaline cells, some solitary or in groups of uniporose retort cells, with more or less conspicuous necks.

Sphagnum fuscum

Sphagnum sect. Acutifolia

Phenology Capsules mature late summer.
Habitat Mires, hummocks, fens
Elevation low to high elevations
Distribution
from FNA
AK; CA; CO; CT; ID; IL; IN; MA; MD; ME; MI; MN; MT; NC; NH; NJ; NY; OH; OR; PA; RI; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; NU; ON; PE; QC; SK; YT; Greenland; Eurasia
[WildflowerSearch map]
Worldwide except Antarctica
Discussion

Sphagnum fuscum is common in ombrotrophic mires and alpine mountain summits where it may form small to large hummocks to 1 m in height, more infrequently in weakly minerotrophic mires and richer fens.

Sporophytes are common in Sphagnum fuscum, which is associated with S. angustifolium, S. fallax, S. magellanicum, S. papillosum, and more infrequently with S. teres, and S. warnstorfii in richer sites. Very widespread but generally easily recognized, it is the only small brown hummock-forming species of sect. Acutifolia over most of its range. There are some significant variations in this species. The stem leaves can vary from having a rounded, entire apex to having a somewhat flat and lacerate apex. The branches also vary from being unranked and slender to 5-ranked and blunt. The color also can vary from a light to a dark brown. There does not seem, however, to be any consistent pattern to these variations and thus no taxonomic recognition has been given to them. See also discussion under 73. S. flavicomans.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 60 (25 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Branch leaves with denticulate margin along a resorption furrow.
S. molle
1. Branch leaf margins plain and bordered without a resorption furrow
→ 2
2. Stem leaves with broad lacerate to fimbriate apex
→ 3
2. Stem leaves with acute, slightly toothed, notched, erose, or rounded apex
→ 11
3. Stem leaves with broad, lacerate apex equal to or less than one half the width of the leaf
→ 4
3. Stem leaves with broad lacerate apex greater or equal to one half the width of the leaf
→ 7
4. Plants red-pigmented
→ 5
4. Plants brown-pigmented, branch leaves ovate-lanceolate and relatively shallow or moderately concave
→ 6
5. Branch leaves ovate and deeply concave, stem cortex aporose
S. andersonianum
5. Branch leaves ovate-lanceolate and only slightly concave, stem cortex usually porose
S. russowii
6. Branch leaves greater than 1.4 mm.
S. arcticum
6. Branch leaves less than 1.4 mm.
S. fuscum
7. Stem leaves spatulate, fimbriate to lacerate across broad apex and along the margins for one-half or more the length; plants slender with conspicuous terminal bud and frequently with numerous sporophytes.
S. fimbriatum
7. Stem leaves lingulate, fimbriate across the apex; plants small to moderate-sized and rigid, terminal bud if present not conspicuous, sporophytes may or may not be present
→ 8
8. Branch fascicles of three spreading and one to two pendent branches; plants green to variegated green and red or red-brown, sporophytes usually present.
S. rubiginosum
8. Branch fascicles of two spreading and one to two pendent branches; plants green or variegated green and brown or golden brown, sporophytes usually not present
→ 9
9. Surface cells of the stem predominately aporose, but some cells with one elliptical pore at distal cell end; branch leaves longer than 1.4 mm; stem leaves usually longer than 1.2 mm; plants typically brown to dark brown.
S. arcticum
9. Surface cells of the stem usually porose with a single elliptical pore in distal portion of cell, but usually free from the cell end wall; branch leaves shorter than 1.4 mm; most stem leaves shorter than 1.2 mm; plants green to brown
→ 10
10. Stem leaf hyaline cells frequently septate, strongly so along margins in upper half.
S. fimbriatum
10. Stem leaves only occasionally septate.
S. girgensohnii
11. Plants brown colored; stem brown in green forms
→ 12
11. Plants red, purple-red; stem green, yellow-green, red or pink in green forms
→ 18
12. Plants without conspicuous metallic sheen when dry
→ 13
12. Plants with metallic sheen when dry
→ 15
13. Stem leaves lingulate; branch leaves equal to or less than 1.3 mm; plants small
S. fuscum
13. Stem leaves lingulate- triangular, broadly ovate-triangular to sublingulate; branch leaves greater than 1.3 mm, plants moderate in size
→ 14
14. Stem leaves lingulate-triangular, 1.5-2 mm, apex right angled to apiculate, retort cells with conspicuous neck; northeastern North American coastal regions south to Delaware.
S. flavicomans
14. Stem leaves broadly oblong-ovate to sublingulate, 1.2-1.8 mm, apex broadly acute to narrowly truncate and toothed; branch leaves loosely arranged and spreading, abruptly involute-acuminate in distal third of leaf from ovate to elliptic base, 1.3-2 mm; retort cells with very short or no noticeable neck; one known locality, in British Columbia.
S. junghuhnianum
15. Branch leaves 5-ranked; stem leaves with rounded apices frequently fimbriate, plants very dark brown
→ 16
15. Stem leaves unranked, with hyaline cells rarely more than once septate and apices rarely fimbriate
→ 17
16. Plants with purplish tinge; stem leaves lingulate, hyaline cells in middle of leaf 0-1-septate.
S. beothuk
16. Plants with deep red tinge; stem leaves triangular-lingulate, hyaline cells in middle of leaf 1-2-septate
S. bergianum
17. Stem leaves lingulate-triangular to lingulate, 1-1.5 mm, apex broadly rounded to obtusely angled, and sometimes apiculate, border strongly broadened at base; branch leaves 1.2-1.7 mm, ovate-lanceolate and short-pointed; plants yellowish brown to dark brown.
S. subfulvum
17. Stem leaves oblong-triangular, 1.3-1.7 mm, apex broadly acute and usually narrowed to a concave cuspidate point, border slightly broadened at based; branch leaves 1.5-2 mm, narrow-lanceolate, apex recurved when dry; plants yellow-brown and tinged with pink to purplish red
S. subnitens
18. Branch leaf hyaline cells in apical region of abaxial surface with very small (less than 2 µm), round, strongly ringed pores; branch leaves strongly 5-ranked.
S. warnstorfii
18. Branch leaf hyaline cells in apical region on abaxial surface with moderate to large (more than 3 µm) pores, with moderate to no observable rings; branch leaves variously ranked
→ 19
19. Stem leaves triangular to triangular-lingulate
→ 20
19. Stem leaves variously shaped, but not triangular to triangular-lingulate, border thickness various at base
→ 22
20. Branch leaves strongly 5-ranked.
S. quinquefarium
20. Branch leaves unranked
→ 21
21. Stem leaves not strongly bordered basally, 1 hanging branch per fascicle
S. sitchense
21. Stem leaves strongly bordered basally, 2 hanging branches per fascicle.
S. subtile
22. Stem leaves lingulate to spatulate, broadest above middle, toothed across broad truncate apex; branch leaves oblong-ovate to elliptic, 1.3-2 mm, with 6-12 teeth across broad apex
S. angermanicum
22. Stem leaves variously shaped, broadest at base; branch leaves with few or no teeth across narrow apex
→ 23
23. Outer stem cortical cells porose.
S. russowii
23. Outer stem cortical cells aporose
→ 24
24. Branch leaves 5-ranked
→ 25
24. Branch leaves unranked
→ 28
25. Stem leaves usually less than 1.1 mm.
S. talbotianum
25. Stem leaves usually more than 1.1 mm
→ 26
26. Stem leaves broadly triangular to triangular-lingulate; branch leaves straight.
S. wilfii
26. Stem leaves lingulate to lingulate-triangular; branch leaves straight to subsecund
→ 27
27. Stem leaves narrowly lingulate-triangular, 1.2-1.8 mm, margins nearly parallel for 3/4 the length of the leaf, apex acute to apiculate, weakly to moderately broadened border at base with the total stem leaf border width less than 0.2 mm; stem leaf hyaline cells rhombic in shape and 0-1-septate; branch leaves narrowly ovate-lanceolate and nearly all straight.
S. bartlettianum
27. Stem leaves lingulate to lingulate-triangular, 1.2-1.5 mm, margins not strictly parallel in proximal portion of leaf, apex broadly rounded, acute in hemiisophyllous forms, strongly bordered at base with the total stem leaf border width usually greater than 0.2 mm; stem leaf hyaline cells rhombic in shape and with at least some in the middle of leaf 2-septate; branch leaves ovate to ovate-lanceolate and falcate-secund on at least some branches.
S. rubellum
28. Branch fascicles with nearly all having two spreading and one pendent branch; branch leaves small, usually less than 1.1 mm, ovate and concave; stem leaves lingulate, usually less than 1.2 mm, apex rounded to slightly apiculate; capitulum diameter usually less than 2.8 mm.
S. andersonianum
28. Branch fascicles of two spreading and two pendent branches, some fascicles with a single pendent branch; branch leaves moderate in size, longer than 1.1 mm, ovate to ovate-lanceolate, not particularly strongly concave; stem leaves elongate triangular-lingulate, usually longer than 1.2 mm, apex acute and usually toothed; capitulum diameter usually greater than 3 mm
→ 29
29. Plants with conspicuous metallic sheen when dry.
S. subnitens
29. Plants lacking conspicuous metallic sheen when dry
→ 30
30. Stem leaves variously fibrillose or efibrillose, triangular- lingulate, small to moderate in size (1.2-1.4 mm, 0.5-0.8 mm wide at base), border at base moderately broadened with a total border width of 0.15-0.25 mm; branch leaves ovate-lanceolate, 1.1-1.4 mm, large round pores restricted to proximal sides and portions of adaxial surface.
S. capillifolium
30. Stem leaves usually fibrillose throughout, elongate-triangular to elongate triangular-ovate, moderate in size (1.3-1.7 mm, 0.3-0.4 mm wide at base), border at base only slightly broadened with total border width of 0.15 mm or less; branch leaves ovate, 1.2-1.7 mm, large round pores throughout adaxial surface.
S. tenerum
Source FNA vol. 27, p. 94. FNA vol. 27, p. 85.
Parent taxa Sphagnaceae > Sphagnum > sect. Acutifolia Sphagnaceae > Sphagnum
Sibling taxa
S. affine, S. alaskense, S. andersonianum, S. angermanicum, S. angustifolium, S. annulatum, S. aongstroemii, S. arcticum, S. atlanticum, S. austinii, S. balticum, S. bartlettianum, S. beothuk, S. bergianum, S. brevifolium, S. capillifolium, S. carolinianum, S. centrale, S. compactum, S. contortum, S. cribrosum, S. cuspidatum, S. cyclophyllum, S. fallax, S. fimbriatum, S. fitzgeraldii, S. flavicomans, S. flexuosum, S. girgensohnii, S. henryense, S. imbricatum, S. inexspectatum, S. inundatum, S. isoviitae, S. jensenii, S. junghuhnianum, S. kenaiense, S. lenense, S. lescurii, S. lindbergii, S. macrophyllum, S. magellanicum, S. majus, S. mcqueenii, S. mendocinum, S. microcarpum, S. mirum, S. mississippiense, S. molle, S. obtusum, S. oregonense, S. orientale, S. pacificum, S. palustre, S. papillosum, S. perfoliatum, S. perichaetiale, S. platyphyllum, S. portoricense, S. pulchrum, S. pylaesii, S. quinquefarium, S. recurvum, S. riparium, S. rubellum, S. rubiginosum, S. rubroflexuosum, S. russowii, S. sitchense, S. splendens, S. squarrosum, S. steerei, S. strictum, S. subfulvum, S. subnitens, S. subsecundum, S. subtile, S. talbotianum, S. tenellum, S. tenerum, S. teres, S. torreyanum, S. trinitense, S. tundrae, S. viride, S. warnstorfii, S. wilfii, S. wulfianum
Subordinate taxa
S. andersonianum, S. angermanicum, S. arcticum, S. bartlettianum, S. beothuk, S. bergianum, S. capillifolium, S. fimbriatum, S. flavicomans, S. fuscum, S. girgensohnii, S. junghuhnianum, S. molle, S. quinquefarium, S. rubellum, S. rubiginosum, S. russowii, S. sitchense, S. subfulvum, S. subnitens, S. subtile, S. talbotianum, S. tenerum, S. warnstorfii, S. wilfii
Synonyms S. acutifolium var. fuscum, S. tenuifolium, S. vancouveriense S. section Acisphagnum, S. section Acuta, S. section Fimbriata, S. section Litophloea, S. section Longifolia, S. section Mollia, S. section Pyncnosphagnum, S. section Truncata
Name authority (Schimper) H. Klinggraff: Schriften Phys.-Ökon. Ges. Konigsberg 13: 4. (1872) Wilson: Bryol. Brit., 20. (1855)
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