Sphagnum sect. Subsecunda

Plants erect to prostrate, extremely variable, capitulum rarely well developed; green, yellowish, light brown, golden brown, reddish brown to dark brown. Stem green to dark brown, superficial cortex of 0–3 layers of efibrillose, non-ornamented, enlarged, thin-walled cells; cells in outer layer aporose or with single round to elliptical wall thinning adjacent to the distal cell wall, visible only with heavy staining. Stem leaves varying from smaller than to larger than branch leaves; triangular, ovate to lingulate; with rounded and sometimes erose apex; border entire; hyaline cells rhomboid to S-shaped, non-ornamented, efibrillose to fibrillose, aporose to sometimes porose, non- to multiply septate; neither surface resorbed. Branches not always clearly dimorphic, spreading and pendent branches very similar. Branch fascicles 1–3 spreading and 0–2(–4) pendent. Branch stems green, surrounded by 1 layer of efibrillose, non-ornamented, thin-walled, inflated cells, with solitary short-necked retort cells or with conspicuously necked retort cells, interspersed with primarily aporose rectangular-shaped cells. Branch leaves oval, ovate or ovate-lanceolate; hyaline cells fibrillose, non-ornamented; convex surface mostly with numerous elliptical to round pores (8–24 per cell) in rows along commissures on convex surface, concave surface with fewer or no pores; chlorophyllous cells elliptical in transverse section, ± equally exposed on both surfaces or slightly more on convex surface, end walls not thickened. Sexual condition dioicous. Capsule with few pseudostomata. Spores 22–41 µm, with or without raised surface sculpture on distal surface; proximal laesura more than 0.5 spore radius.

Distribution

Worldwide except Antarctica.

Discussion

Species 99 (13 in the flora).

Selected References

None.

Lower Taxa

Sphagnum carolinianum, Sphagnum contortum, Sphagnum cyclophyllum, Sphagnum inexspectatum, Sphagnum inundatum, Sphagnum lescurii, Sphagnum microcarpum, Sphagnum oregonense, Sphagnum orientale, Sphagnum perfoliatum, Sphagnum platyphyllum, Sphagnum pylaesii, Sphagnum subsecundum

Key

1	Stem cortex undifferentiated, superficial layer composed of small thick-walled cells	Sphagnum microcarpum
1	Stem cortex differentiated with one or more superficial layers of enlarged thin-walled cells	> 2
2	Stem cortex of more than 1 superficial layer of enlarged, thin-walled cells	> 3
2	Stem cortex 1 superficial layer of enlarged, thin-walled cells	> 7
3	Stem leaves broadly ovate and completely fibrillose, fascicles of 3 branches; terminal bud large, round.	Sphagnum platyphyllum
3	Stem leaves lingulate and fibrillose apically; fascicles most 4 or more branches; terminal bud, if any, small	> 4
4	Stem leaf hyaline cells without parallel septations, usually non-septate; branch leaves 1.2-2 mm.	Sphagnum contortum
4	Stem cortex partly one and partly two layers of enlarged thin-walled cells	> 5
5	Branch leaf convex surface commissural pores equal to or less than 1 µm.	Sphagnum orientale
5	Branch leaf convex surface commissural pores 3 µm or more	> 6
6	At least some stem leaf hyaline cells with 2 or more parallel septations; branch leaves 2.2 mm or longer.	Sphagnum carolinianum
6	Stem leaf hyaline cells without parallel septations, leaves less than 2.2 mm	Sphagnum inexspectatum
7	Stem simple without branches	> 8
7	Stems with branches arranged in fascicles	> 9
8	Hyaline cells of stem and branch leaves with numerous minute, rounded pores on free surface, stem and branch leaves similar and very long (3.5-4 mm), some stem cortical cells with a single wall thinning at the distal end of the cell.	Sphagnum cyclophyllum
8	Hyaline cells of stem and branch leaves without pores on superficial surface or with 1-3 small pores in apical ends and angles of cells, stem leaves longer (1.5-2.5 mm) than branch leaves (0.9-1.2 mm), stem cortical cells aporose.	Sphagnum pylaesii
9	Hyaline cells of branch leaves without pores on convex surface or with 1-3 small pores in cell apical ends and angles, hyaline cells of branch leaves with thick fibrils that nearly divide the cells into a series of squarish segments.	Sphagnum pylaesii
9	Hyaline cells of branch leaves with rows of commissural pores or with 1-5 pores per cell free from the commissures on the convex surface, hyaline cells with thin fibrils	> 10
10	Stem leaves greater than 1.2 mm, lingulate to ovate-lingulate, generally fibrillose for more than 1/3 their length.	Sphagnum lescurii
10	Stem leaves equal to or less than 1.2 mm, triangular to triangular-lingulate, generally fibrillose for 1/3 or less their length	> 11
11	Branch leaf hyaline cells lacking pores along the commissures but up to 5 small pores free from the commissures on convex surface.	Sphagnum oregonense
11	Branch leaf hyaline cells with continuous rows of pores along the commissures and sometimes with few to numerous pores free from the commissures on convex surface	> 12
12	Branch leaf hyaline cell pores less than or equal to 3 µm, often with 1- 2 rows of pores free from the commissures.	Sphagnum perfoliatum
12	Branch leaf hyaline cell pores more than 3 µm, lacking pores free from the commissures	> 13
13	Stem leaves longer than 0.7 mm; branch leaves equal to or greater than 1.2 mm, mostly straight.	Sphagnum inundatum
13	Stem leaves less than 0.7 mm; branch leaves less than 1.2 mm, often subsecund.	Sphagnum subsecundum