Sphagnum sect. Subsecunda |
Sphagnum platyphyllum |
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flat-leaf peat-moss, sphagnum |
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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. |
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Branches | not always clearly dimorphic, spreading and pendent branches very similar. |
short and blunt, sometimes lacking completely and plants simplex. |
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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. |
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Sexual condition | dioicous. |
dioicous. |
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Capsule | with few pseudostomata. |
exserted, with few pseudostomata. |
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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. |
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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. |
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Sphagnum sect. Subsecunda |
Sphagnum platyphyllum |
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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 |
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 |
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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.) |
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Key |
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Source | FNA vol. 27, p. 78. | FNA vol. 27, p. 83. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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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) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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