Sphagnum tenerum
Sphagnum sect. Acutifolia
sphagnum
leaves 1.4–1.8 mm, elongate-triangular, lingulate-triangular, hemiisophyllous forms elongate triangular-ovate, 1.4–1.8 mm, apex usually conspicuously toothed, border narrow at base (less than 0.25 width);
hyaline cells narrowly rhombic to S-shaped, can be efibrillose and aporose but more commonly fibrillose and porose, 0–1-septate.
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.
turgid and terete, leaves, not 5-ranked.
dimorphic, spreading branches usually longer and thicker than pendent branches.
ovate, 1.1–1.7 mm, slightly concave, straight, apex weakly involute and conspicuously toothed;
hyaline cells on the convex surface with round to elliptic pores along the commissures, grading from moderate-sized pores near apex to large pores at leaf base, concave surface with large round pores throughout.
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.
uncertain, monoicous or dioicous or possibly both.
usually dioicous, occasionally monoicous.
equal to or less than 2 mm, with few to many pseudostomata.
22–25 µm, finely roughened.
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.
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 tenerum
Sphagnum sect. Acutifolia
Sporophytes are uncommon in Spagnum tenerum. The sexual condition is uncertain because of past taxonomic confusion with S. capillifolium (R. E. Andrus 1980). Sphagnum tenerum is usually described (incorrectly) as having hemiisophyllous stem leaves, and many collections of other species of sect. Acutifolia with such leaves have been called S. tenerum. When correctly characterized, S. tenerum is can be confused only with S. capillifolium, with which it has only a very small range overlap. Microscopically, besides the otherwise quite different S. angermanicum, S. tenerum is the only species of sect. Acutifolia with large round free pores in most of the branch leaf hyaline cells on their concave surfaces. See also discussion under 71. S. capillifolium. Sexual condition and spore features were taken from H. A. Crum (1984).
The name Sphagnum evansii Warnstorf has also been used for this taxon.
(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.)
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 |
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