Flora of North America species comparison

leaves lingulate-triangular to lingulate, 1–1.4 mm, apex broadly rounded but becoming acute in hemiisophyllous forms, border strongly developed at base (more than 0.25 width);

hyaline cells rhombic and 0–3-septate with some cells in leaf midregion 2–septate.

leaves may be less fibrillose or efibrillose and less porose or aporose than the branch leaves, often septate, a distinct border of narrow linear chlorophyllous cells often along margins and at base, and with a greater width:length ratio than branch leaves in anisophyllous forms, partly differentiated in hemiisophyllous forms, and identical in isophyllous forms.

weakly to strongly 5-ranked.

typically dimorphic as spreading and pendent branches, but some species lack branches or branches are not clearly differentiated, pendent branches typically more slender than spreading branches and with a tendency to adhere to and cover the stem.

ovate to ovate-lanceolate, 0.9–1.2 mm, concave, subsecund on some branches, apex involute;

hyaline cells on convex surface with numerous round to elliptic pores along the commissures, grading from small round pores near apex to round pores near base, on concave surface with large round pores in proximal portions of leaf.

with 2/5 phyllotaxy, of a 1-stratose network of alternating chlorophyllous and hyaline cells;

hyaline cells usually S-shaped, rarely rhomboid, nearly always strengthened with conspicuous spiral fibrils, small to large, round to elliptic and sometimes ringed pores occur along commissures or rarely on cell lumen, convex surface typically with more pores per cell than concave surface; chlorophyllous cells may be enclosed on both surfaces, more broadly exposed on one surface or equally exposed on both surfaces as viewed in transverse section, adjacent cell walls typically smooth, but various types of cell wall projections may be clearly visible in transverse section.

dioicous.

dioicous or monoicous; stalked globose antheridia borne at the tips of branches usually with swollen colored tips of branches near capitulum; long-necked archegonia borne on short branches singly surrounded by perichaetial leaves that are typically longer than branch leaves.

spherical, brown to black, lacking an annulus or peristome with a operculum convex;

spore sac amphithecial in origin, over-arching columella.

membranous.

18–33 µm, coarsely papillose on both surfaces;

proximal laesura less than 0.4 spore radius.

tetrahedral, with prominent trilete mark, fine to coarse superficial surface, distal surface may have raised Y-mark, bifurcated Y-mark sculpture, or none.

fascicles with 2 spreading and 1–2 pendent branches.

fascicles typically with 2 spreading and 1–2 pendent branches, but there may be up to 12(–14) per fascicle.;

branch stems typically green, with a superficial layer of inflated retort cells; these grouped or solitary, usually porose at the distal end with a conspicuous or inconspicuous neck.

typically 1-stratose, gametophyte developing from lateral margin.