Sphagnum sect. Subsecunda
Sphagnum microcarpum
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.
leaves isophyllous, ovate to ovate-lanceolate, 2.2–2.8 mm;
apex rounded;
hyaline cells nonseptate, convex surface with 6–12 pores per cell along commissures, concave surface aporose.
not always clearly dimorphic, spreading and pendent branches very similar.
straight and short.
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.
ovate, 1.3–1.7 mm;
hyaline cells on convex surface with 8–18 elliptic pores more than 8 µm, concave surface aporose.
dioicous.
unknown.
with few pseudostomata.
not seen.
22–41 µm, with or without raised surface sculpture on distal surface;
proximal laesura more than 0.5 spore radius.
not seen.
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.
fascicles nearly all with 2 spreading branch only.
Sphagnum sect. Subsecunda
Sphagnum microcarpum
Species 99 (13 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Sporophytes are rare in Sphagnum microcarpum, which grows over bare soil in a manner similar to that of S. cyclophyllum and S. fitzgeraldii. It is now recognized as separate from S. cyclophyllum, with which it has been treated as synonymous in the past. Besides the microscopic differences, S. microcarpum has a compact upright growth form quite unlike that of typical S. cyclophyllum. Sphagnum microcarpum is nearly always branched whereas S. cyclophyllum is nearly always simplex.
The name Sphagnum mobilense Warnstorf also has been applied to this taxon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stem cortex undifferentiated, superficial layer composed of small thick-walled cells | S. 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. | S. 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. | S. 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. | S. 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. | S. carolinianum |
6. Stem leaf hyaline cells without parallel septations, leaves less than 2.2 mm | S. 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. | S. 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. | S. 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. | S. 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. | S. 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. | S. 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. | S. 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. | S. inundatum |
13. Stem leaves less than 0.7 mm; branch leaves less than 1.2 mm, often subsecund. | S. subsecundum |
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