Sphagnum andersonianum
Sphagnum inexspectatum
Anderson's sphagnum
leaves lingulate, 0.9–1.2(–1.4) mm, apex rounded-erose to sometimes slightly apiculate, border moderately strong and broadened at the base (to 0.8 the width);
hyaline cells rhombic, 0–1-septate, usually efibrillose.
leaves triangular-lingulate to ovate-lingulate, 0.8–0.9 mm, apex rounded, straight;
hyaline cells mostly non-septate, fibrillose in distal 1/3–2/3 of leaf, a few ringed pores at corners of cells and along commissures on convex surface, ringed pores along the commissures on the concave surface in greater numbers than on convex surface.
not or slightly 5-ranked, lax.
short, not turgid.
ovate, 0.8–1.4 mm, distinctly concave, straight, apex dentate and involute;
border entire;
hyaline cells on convex surface with elliptic pores along the commissures, grading from smaller pores near the apex to larger pores at the base, concave surface with large round pores on the proximal portions of the leaf.
broad-ovate to ovate-lanceolate, 0.9–2.1 mm, straight;
hyaline cells with numerous ringed pores (10–20) along the commissures on the convex surface, a few pseudopores and ringed pores (less than 8 per cell) occur on the cell angles on the concave surface.
dioicous.
dioicous.
exserted, with few pseudostomata.
18–24 µm; coarsely papillose on both surfaces;
proximal laesura less than 0.5 the length of the spore radius.
36–39 µm; coarsely papillose on both surfaces;
proximal laesura less than or equal to 0.5 spore radius.
fascicles with 2 spreading and 1–2 pendent branches.
fascicles with 2–3 spreading and 1–2 pendent branches.
Sphagnum andersonianum
Sphagnum inexspectatum
Sporophytes are uncommon in Sphagnum andersonianum. Its distribution is uncertain due to past taxonomic confusion with S. rubellum, S. capillifolium, and other closely related species in sect. Acutifolia. This is one of the most hydrophytic species of the section and is often associated with S. angustifolium, S. fallax, and S. rubellum. It is often not easily distinguished from S. rubellum, with which it may intergrade in a manner similar to that already demonstrated for S. rubellum and S. capillifolium by N. Cronberg (1997, 1998). Phenotypically S. andersonianum is a softer, paler plant with branch leaves that are more ovate and concave on branches that are less 5-ranked. Sphagnum rubellum also has the branch leaves sometimes subsecund while in S. andersonianum they are straight. Ecologically S. rubellum is an open mire species of usually ombrotrophic conditions, where it often forms hummocks, while S. andersonianum occurs in more sheltered sites where there is some mineral influence. Where they occur together, S. rubellum is on the tops of hummocks and S. andersonianum is on the hummock sides and bases. Microscopically S. rubellum has stem leaves with at least some of the hyaline cells twice septate, while in S. andersonianum none are twice septate.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Sphagnum inexpectatum is frequently collected with S. tenellum, S. pacificum, S. andersonianum, and S. rubellum in weakly minerotrophic blanket mires. It is similar in size to S. subsecundum, with which its range completely overlaps. The latter species has many of the branch leaves subsecund while those of S. inexspectatum are straight. The stem leaves of S. inexspectatum are also conspicuously larger than those of S. subsecundum.
Microscopically Sphagnum inexspectatum has a stem cortex that has enlarged thin-walled cells that form 1–2 layers, whereas S. subsecundum has only one. The stem leaves of S. inexspectatum also have numerous commissural pores in the hyaline cells in the distal half of the concave surface, whereas S. subsecundum has only a few if any in this region and these are more free than commissural.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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