Flora of North America species comparison

fusiform, fascicled, thickened, epidermis splitting or peeling near base.

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.

subterete or somewhat angled, with narrow raised lines or wings decurrent from leaf axils, 40–150 cm, well branched in distal 1/2, glabrous or sparsely to densely strigillose.

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.

stipules narrowly deltate, 0.05–0.2 × 0.05–0.1 mm;

petiole 0.1–0.3(–0.7) cm;

blade lanceolate-elliptic, (0.6–)2–12 × (0.3–)1–1.5(–2.5) cm, base attenuate, margins entire, apex acute, surfaces strigillose throughout or glabrate with strigillose veins;

bracts often reduced and more linear.

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.

leafy racemes, flowers solitary in leaf axils;

bracteoles linear-lanceolate, 1–2.5 mm, margins entire, apex acute or subacuminate, glabrous or with scattered hairs, attached near base of ovary.

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.

sepals narrowly ovate-deltate, (6–)6.5–9.5 × 4–6.5 mm, margins entire, apex acute to obtuse, surfaces strigillose, sometimes mixed with villous hairs, or glabrate;

petals cordate, 10–14 ×8–12 mm, base attenuate, apex emarginate;

filaments opaque white, awl-shaped, 1–3 mm, anthers 1–1.7 × 0.6–0.8 mm;

ovary subcuboid to globose, 2.5–4 ×2.5–3.5 mm;

nectary disc slightly elevated on ovary apex, 0.8–1.5 mm diam., 4-lobed, ringed with soft, curly hairs or glabrous;

style 1.5–2.4 mm, glabrous, stigma light yellow, capitate to hemispherical, 1–1.3 × 1.4–2 mm, shallowly 4-lobed, not or scarcely exserted beyond anthers.

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.

subcuboid to squarish globose, 4–6(–7) × 4–6 mm, 4-angled and 4-winged, wings 0.3–1.5 mm wide, pedicel 2–7 mm.

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

light brown, oblong to reniform, 0.5–0.8 × 0.2–0.4 mm, surface cells elongate transversely to seed length.

= 16.

= 16.