Flora of North America species comparison

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.

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.

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.

dimorphic, spreading branches tumid, pendent branches usually shorter and more slender.

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.

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.

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.

usually dioicous.

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

spore sac amphithecial in origin, over-arching columella.

2 mm or more.

membranous.

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

typically 22–30 µm, distal surface sculpture may be present;

proximal laesura usually more than 0.5 spore radius.

typically 1-stratose, gametophyte developing from lateral margin.

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.

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.