Flora of North America species comparison

erect or ascending, slightly ridged, usually well branched, 12–55(–62) 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 narrowly ovate to narrowly lanceolate, 0.2–0.3 × 0.1–0.2 mm;

stolons: petiole narrowly attenuate, 0.05–0.5 cm, blade narrowly obovate or oblanceolate to spatulate, 0.5–2 × 0.1–0.6 cm;

stems: sessile, blade linear to linear-oblanceolate, 1.5–4 × 0.1–0.4(–0.6) cm, base very narrowly cuneate, margins entire with obscure hydathodal glands, apex acuminate to acute;

bracts linear, 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.

leafy spikes, flowers solitary in leaf axils;

bracteoles attached 0–1.5 mm distal to base of ovary, very narrowly oblanceolate to linear, (1.5–)2.5–9(–13) × 0.2–0.8 mm, margins entire, apex acute.

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 ascending, green, narrowly lanceolate-deltate, (3–)4–7 × 1.1–1.7 mm, margins entire, apex narrowly acute, surfaces glabrous or minutely papillose;

petals narrowly obovate-elliptic, 4–6 × 2–4 mm, base obtuse, apex obtuse or rounded;

filaments pale yellow, (1.3–)1.5–2.5(–3) mm, anthers oblong, 0.6–1.1 × 0.5–0.8 mm;

pollen shed in tetrads;

ovary subcylindric, 3–4 × 1–1.5 mm;

nectary disc elevated 0.3–0.7 mm on ovary apex, bright yellow, 0.8–1.5 mm diam., prominently 4-lobed, minutely papillose;

style yellow, 1.25–2.5 mm, glabrous, stigma subcapitate, 0.3–0.6 × 0.6–0.8 mm, shallowly 4-lobed, 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.

subcylindric, terete or slightly angled, 5–10(–12) ×1.3–2(–2.2) mm, hard-walled, irregularly dehiscent, pedicel 0 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.

reddish brown, oblong-elliptic, 0.6–0.7 × 0.2–0.3 mm, surface cells nearly isodiametric.

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

= 16.

= 16.