The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

flat-leaf peat-moss, sphagnum

Habit Plants erect to prostrate, extremely variable, capitulum rarely well developed; green, yellowish, light brown, golden brown, reddish brown to dark brown. Plants small to moderate-sized, unbranched or sparsely branched; green, golden brown to brown, capitulum small with a large and conspicuous terminal bud.
Stem(s)

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 broadly ovate, 1.2–2.2 mm; straight;

apex rounded;

hyaline cells non-septate, convex surface with numerous small pores (less than or equal to 1/6 cell diameter) forming a continuous row along the commissures, concave surface aporose or with a few scattered pores along the commissures and cell ends.

Branches

not always clearly dimorphic, spreading and pendent branches very similar.

short and blunt, sometimes lacking completely and plants simplex.

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.

broadly ovate, 1.4–2.5(–3) mm; straight;

apex rounded;

hyaline cells as in stem leaf.

Sexual condition

dioicous.

dioicous.

Capsule

with few pseudostomata.

exserted, with few pseudostomata.

Spores

22–41 µm, with or without raised surface sculpture on distal surface;

proximal laesura more than 0.5 spore radius.

23–35 µm;

papillose on both surfaces, with indistinct Y-mark sculpture on distal surface;

proximal laesura 0.5 spore radius or less.

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.

fascicles of 1–3 branches, 1–2 of these spreading, branches usually not numerous.

Sphagnum sect. Subsecunda

Sphagnum platyphyllum

Phenology Capsules mature late spring to early summer.
Habitat Typically growing in minerotrophic habitats such as shores of lakes, ponds, streams, flarks of string mires, margins of open fens, especially seasonally flooded sites
Elevation low to high elevations
Distribution
Worldwide except Antarctica
from FNA
AK; AZ; CA; CO; CT; IN; MA; ME; MI; MN; MT; NH; NJ; NY; OH; OR; RI; VT; WI; WY; AB; BC; MB; NB; NF; ON; QC; YT; South America; Greenland; Eurasia
Discussion

Species 99 (13 in the flora).

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

Sporophytes are uncommon in Sphagnum platyphyllum, which can be quite variable in size and the development of branch fascicles, with some forms even being simplex while other forms may have up to three branches per fascicle. The species can usually be recognized by the large stem leaves that are spreading and easily visible because of the scarcity of hanging branches. It should also be noted that in this species and S. contortum the 2–3-layered stem cortex is not an entirely consistent trait, as plants quite typical in all other respects are occasionally found with the cortex only 1-layered, at least in part.

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

Key
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
Source FNA vol. 27, p. 78. FNA vol. 27, p. 83.
Parent taxa Sphagnaceae > Sphagnum Sphagnaceae > Sphagnum > sect. Subsecunda
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. fuscum, 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. 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. carolinianum, S. contortum, S. cyclophyllum, S. inexspectatum, S. inundatum, S. lescurii, S. microcarpum, S. oregonense, S. orientale, S. perfoliatum, S. platyphyllum, S. pylaesii, S. subsecundum
Synonyms S. unranked Subsecunda, S. unranked Cavifolia, S. unranked Comatosphagnum, S. unranked Cyclophylla, S. section Hemitheca S. laricinum var. platyphyllum, S. contortum var. platyphyllum, S. subsecundum var. platyphyllum
Name authority (Lindberg) Schimper: Syn. Musc. Eur. ed. 2, 2: 843. (1876) (Lindberg) Warnstorf: Flora 67: 481. (1884)
Web links