Flora of North America species comparison

erect or somewhat sprawling, slightly to distinctly winged (wings to 1.8 mm wide), branched distally, 40–120(–160) cm, glabrous.

floating or creeping and ascending to erect, terete, 10–100(–300) cm, simple or branched, glabrous or sparsely to densely villous, hairs sometimes viscid on emergent distal stem.

alternate;

stipules ovate-deltate, often narrowly so, 0.2–0.4 × 0.1–0.3 mm, succulent;

stolons: petiole 0.15–1 cm, blades orbiculate to oblanceolate or broadly elliptic, 0.4–2.6 × 0.4–1.5 cm, base attenuate, apex rounded to subacute;

stems: petiole 0–0.3 cm, blade lanceolate-elliptic or very narrowly elliptic to linear, sometimes to oblanceolate or oblanceolate-elliptic near base, 1.8–10 × 0.2–1.3(–2) cm, base narrowly cuneate or attenuate, margins subentire with remote hydathodal glands, rarely minutely papillose-serrulate near apex, apex acute to narrowly acute, leaves on side branches much reduced;

bracts much reduced.

stipules broadly ovate-deltate, 0.6–1.6 × 0.4–1 mm, succulent, apex acute or obtuse, gland-tipped, rarely divided into 3 parts;

petiole flattened or narrowly winged, 0.2–6 cm;

blade narrowly oblong or elliptic to ovate, broadly obovate, or orbiculate, (0.4–)1–10 × 0.4–4 cm, base narrowly cuneate or attenuate, margins entire, apex obtuse or rounded to acute, sometimes mucronate or glandular-mucronate, surfaces of floating leaves glabrous, those of emergent leaves glabrous to sparsely or densely strigillose at least adaxially;

bracts scarcely reduced.

sometimes congested, leafy spikes or racemes, flowers solitary in distal leaf axils;

bracteoles attached near base of ovary, lanceolate-elliptic or narrowly so, 2.4–4.7 × 0.6–1.5 mm, margins minutely papillose or smooth, apex acute, surfaces glabrous.

on emergent stems sometimes in leafy racemes, flowers solitary in leaf axils;

bracteoles (rarely absent), deltate, squamate, 0.5–1 × 0.5–1 mm, apex acute, attached near base or on lower 1/2 of ovary.

sepals spreading to reflexed, creamy white adaxially, broadly ovate-deltate, 2–4 × 1.6–4 mm, margins smooth or minutely papillose-serrulate, apex acute or acuminate, surfaces glabrous;

petals 0;

filaments nearly translucent, 1.1–1.7 mm, slightly dilated near base, anthers 0.5–0.9 × 0.4–0.7 mm;

pollen shed singly;

ovary obpyramidal, sharply 4-angled, 2–3.8 × 2–3.5 mm;

nectary disc elevated 0.5–0.8 mm on ovary apex, bright yellow, square with rounded corners, 2–3.3 mm diam., prominently 4-lobed, glabrous;

style pale green, 0.8–1.3 mm, glabrous, stigma pale yellow, subglobose, 0.3–0.6 × 0.3–0.7 mm, shallowly 4-lobed on top, not exserted beyond anthers.

sepals narrowly deltate or lanceolate, 3–12 × 1.5–4 mm, apex acute or acuminate, surfaces glabrous or sparsely to densely hirtellous;

petals yellow, obpyramidal,7–24 × 4–13 mm, apex mucronate or emarginate, up-curved;

stamens 10(or 12), in 2 unequal series, bright yellow, filaments suberect or reflexed, shorter ones 1.4–4.2 mm, longer ones (1.9–)3.3–6 mm, anthers oblong, 0.5–2.2 mm;

ovary subcylindric or truncate, 6–20 × 1.5–3 mm, apex somewhat broader, glabrous or sparsely to densely hirtellous;

nectary disc slightly raised on ovary apex, 2–2.5 mm diam., lobed, glabrous or fringed with long hairs;

style (1.9–)2.4–7.3 mm, glabrous or sparsely to densely hirtellous on proximal 1/2, stigma flattened-globose, 0.9–1.2 × 1–2.5 mm, sometimes shallowly or deeply 5-lobed, as long as or exserted beyond anthers.

obpyramidal, sharply 4-angled and 4-winged, 3–5 × 2.8–4.5 mm, with hard walls somewhat bulging, dehiscent by apical ring, pedicel 0–0.8 mm.

cylindric, subterete to obscurely 5-angled, straight or curved, 10–40 × 2–4 mm, with thick woody walls, irregularly and tardily dehiscent, pedicel 7–60(–90) mm.

light brown, ellipsoid, slightly curved on both ends, 0.6–0.7 × 0.3–0.4 mm, surface cells elongate transversely to seed length.

embedded in elongated piece of endocarp, 1–1.5 × 0.9–1.3 mm.

= 48.

= 16.