Flora of North America species comparison

green or yellow-green, usually brownish with age;

stems of two types, fertile stems erect, branching distally or not, dendroid or not, sterile stems plagiotropic or arching, rarely erect, to 20 cm;

rhizoids brown, macronemata mainly proximal, occasionally along underside of sterile stems, micronemata present.

green or yellow-green, crisped and contorted when dry, flat when moist, ovate, elliptic, oblong-elliptic, or rarely obovate, (3–)4–6(–10) mm;

base narrowly long-decurrent;

margins toothed to near base, smaller leaves sometimes nearly entire, teeth blunt or less commonly sharp, of (1–)2–3(–4) cells;

apex rounded, occasionally truncate or obtuse, rarely retuse, cuspidate or apiculate, cusp occasionally toothed;

costa percurrent, excurrent, or rarely subpercurrent;

medial laminal cells elongate, rarely ± isodiametric (especially near margins), 45–85 µm, less than 1/2 size near margins, in ± longitudinal, occasionally diagonal rows, collenchymatous, sometimes weakly, walls pitted, pits sometimes indistinct or absent;

marginal cells linear, sometimes short-linear or rhomboidal, in (2–)3–4 rows.

green or yellow-green, rarely black with age, variously crisped or contorted when dry, erect-spreading, usually flat, occasionally irregularly wavy or transversely undulate when moist, elliptic, obovate, oblong, oblong-lingulate, oblong-elliptic, or rarely orbicular or diamond-shaped, 1–14 mm;

base decurrent or not;

margins plane, green or yellow-green, 1-stratose, toothed, often to near base, sometimes only distally, rarely entire, teeth single, sharp or blunt, of 1–2(–4) cells, rarely hooked;

apex acute, acuminate, obtuse, rounded, truncate, retuse, or emarginate, mucronate, apiculate, or cuspidate, cusp toothed or not, rarely bent to one side;

costa percurrent, excurrent, or rarely subpercurrent, distal abaxial surface smooth;

medial laminal cells short-elongate, elongate, or ± isodiametric, (15–)30–70(–85) µm, sometimes in diagonal or longitudinal rows, collenchymatous or not, walls pitted or not;

marginal cells differentiated, linear or rhomboidal, in 2–4(–5) rows.

1–3, yellowish or brownish green, 2–4 cm.

single or multiple, yellow, yellow-green, brown, sometimes reddish or greenish, rarely orange, dark red, or blackish with age, 1.2–5 cm, straight to flexuose.

dioicous.

synoicous or dioicous.

pendent, cylindric, 3–4.5 mm, neck not distinct;

operculum conic-apiculate.

horizontal to pendent, yellow or yellowish brown, cylindric, oblong, oblong-cylindric, obovoid, or ovoid, 1.5–5 mm;

operculum conic-apiculate or rostrate;

exostome yellow or brown;

endostome yellow to yellowish brown.

18–24 µm.

18–40 µm.

stems 2–5(–9) cm, not dendroid;

sterile stems to 10 cm.

asexual reproduction usually absent (by stolonlike stems in P. undulatum).