Flora of North America species comparison

1–many, occasionally becoming decumbent.

erect, decumbent and rooting at nodes, or floating, terete, 1–2 mm diam., smooth.

0–2.

0 or 1–2, straw-colored, apex acute.

basal and cauline;

auricles rudimentary or absent;

blade flat, 3–13 cm × 0.3–1.1 mm.

basal 1–3, cauline 1–4;

auricles 0.8–2.1 mm, apex rounded to acute, membranaceous;

blade terete, 3.7–15 cm × 0.4–1.3 mm, occasionally with filiform, flaccid, and floating leaves to 60 cm.

loose and diffuse or less often compact, usually at least ½1/2 total height of plant;

primary bract shorter than inflorescence.

terminal racemes of 2–9 heads, 2–10 cm, branches erect;

primary bract erect;

heads 2–12-flowered, obconic or rarely hemispheric, 4–13 mm diam.

bracteoles 2;

tepals greenish, lanceolate, 3.8–7(–8.5) mm;

inner series slightly shorter, apex sometimes obtuse;

stamens 3–6, filaments (0.7–)1–1.8 mm, anthers 0.3–0.8 mm;

style 0.1–0.2 mm.

tepals light brown or greenish to reddish brown, linear to narrowly lanceolate, apex acute to acuminate-subulate;

outer tepals (2.1–)2.8–4.9 mm;

inner tepals (2.1–)2.8–5.5 mm;

stamens 3 or 6, anthers 1/2–3/4 filament length.

tan to reddish brown, 3-locular, ellipsoid to narrowly so, slightly truncate, 2.7–4 × 1–1.5 mm, sometimes exceeding inner tepals but usually not outer series.

usually exserted, dark brown, 1-locular, ovoid to oblong, (3.2–)3.5–6.1 mm, apex acute to acuminate proximal to beak, valves separating at dehiscence.

yellowish, widely ellipsoid to ovoid, 0.26–0.49, not tailed.

narrowly obovoid to obovoid, 0.6–0.7 mm, not tailed;

body clear yellow-brown..

= ca. 30, ca. 50–60, 2n = ca. 112.

= 27–37, 58–81, 108–115.