Sphagnum sect. Sphagnum |
Sphagnum henryense |
|||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Henry's sphagnum |
|||||||||||||||||||||||||||||||||||||||||||||
Habit | Plants typically large, with distinct capitulum; green, pale green, yellowish, red, tan, brown to dark brown. | Plants moderate-sized to robust, capitulum typically flat, ± 5-radiate and with terminal bud slightly visible; green, pale green, to pale pinkish brown tinged with brown to reddish brown; forming carpets or low hummocks. | ||||||||||||||||||||||||||||||||||||||||||||
Stem(s) | leaves typically as large as or larger than branch leaves, lingulate to ovate-lingulate with broad rounded apex, border fringed; hyaline cells rhomboid, efibrillose or fibrillose, sometimes ornamented, aporose, 0–2-septate, and often resorbed on exterior surface. |
leaves to 1.9 × 1 mm; rarely hemiisophyllous; hyaline cells non-ornamented, nonseptate or septate. |
||||||||||||||||||||||||||||||||||||||||||||
Branches | dimorphic, spreading branches tumid, pendent branches usually shorter and more slender. |
± tapering to a point, leaves spreading to moderately imbricate. |
||||||||||||||||||||||||||||||||||||||||||||
Branch leaves | ovate to broadly ovate, apex cucullate and roughened on convex surface; margin toothed; hyaline cells fibrillose; convex surface pores round to elliptic, usually with 1 at each corner of three adjacent hyaline cells; chlorophyllous cells lenticular to triangular, sometimes with wall ornamentation visible in transverse section; chlorophyllous cells enclosed, equally exposed, or more broadly exposed on concave surface, end walls thickened or unthickened. |
ovate, to 2.7 × 1 mm; hyaline cells on convex surface with numerous small round pores along the commissures, cell walls overlying chlorophyll cells often with a network of irregular worm like ridges although they may be lacking; chlorophyllous cells isosceles-triangular to narrowly ovate triangular in transverse section and just enclosed on convex surface,end wall not thickened. |
||||||||||||||||||||||||||||||||||||||||||||
Sexual condition | usually dioicous. |
dioicous. |
||||||||||||||||||||||||||||||||||||||||||||
Capsule | 2 mm or more. |
with numerous pseudostomata. |
||||||||||||||||||||||||||||||||||||||||||||
Spores | typically 22–30 µm, distal surface sculpture may be present; proximal laesura usually more than 0.5 spore radius. |
24–29 µm; surface finely papillose to nearly smooth. |
||||||||||||||||||||||||||||||||||||||||||||
Branch | fascicles with 2–3 spreading branches and 1–3 pendent branches.; branch stems green, surrounded by 1 layer of enlarged thin-walled cells, typically porose and fibrillose, in some species ornamented on interior wall; retort cells absent. |
fascicles with 2 spreading and 2 pendent branches.; branch stems with hyaline cells non-ornamented; funnel-like projections absent from interior end walls, large round pores on superficial walls. |
||||||||||||||||||||||||||||||||||||||||||||
Sphagnum sect. Sphagnum |
Sphagnum henryense |
|||||||||||||||||||||||||||||||||||||||||||||
Habitat | Poor to medium fens, common in wooded fens and pond margins | |||||||||||||||||||||||||||||||||||||||||||||
Elevation | low to moderate elevations | |||||||||||||||||||||||||||||||||||||||||||||
Distribution | Worldwide except Antarctica |
AK; AL; AR; CA; CT; DC; DE; FL; GA; IL; IN; LA; MA; MD; ME; MI; MO; MS; NC; NH; NJ; NY; OH; OK; OR; SC; TN; TX; VA; VT; WI; WV; BC; NF; NS; PE; Asia |
||||||||||||||||||||||||||||||||||||||||||||
Discussion | Species 54 (12 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The typical form of Sphagnum henryense is a large plant with a quite flat capitulum with a small terminal bud. Microscopically, typical material has distinct ridges on the branch leaf hyaline cells and relatively small and round pores on the branch leaf hyaline cell convex surface. Sphagnum palustre, which has the same branch leaf chlorophyll cell cross section, typically has smooth hyaline cell walls and hyaline cell pores that are larger and more elliptical in shape. However, Sphagnum species are plastic phenotypically and it is common to find plants that cannot be reliably assigned to either S. henryense or S. palustre. For example, some species of Sphagnum that are relatively easy to distinguish on other characteristics, such as S. papillosum, S. alaskense and S. affine, may occasionally completely lack any hyaline cell ornamentation or display it in reduced form. Since these can be distinguished on other characters, the species are still readily identifiable, but when S. henryense lacks the ornamentation, there is no other solid character to distinguish it from S. palustre. Thus, although we can find material from both North American coasts that has good ornamentation (R. E. Andrus 1980), there is much other material that looks in other respects like S. henryense but lacks the ornamentation. Barring taxonomy beyond microscopic examination, many collections of henryense/palustre will of necessity not be absolutely identifiable. Where their ranges overlap, mixed stands may often be found. We believe that the species are still good, but accurate delimitation of their distinctive ecologies and ranges will be very problematic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||||||||||||||||||||||||||||||||||
Key |
|
|||||||||||||||||||||||||||||||||||||||||||||
Source | FNA vol. 27, p. 48. | FNA vol. 27, p. 51. | ||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | ||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | S. henryense var. bartlettii | |||||||||||||||||||||||||||||||||||||||||||||
Name authority | unknown | Warnstorf: Hedwigia 39: 107. (1900) | ||||||||||||||||||||||||||||||||||||||||||||
Web links |