Flora of North America species comparison

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.

erect, subterete, densely branched, 40–120 cm, densely hirtellous.

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.

alternate;

stipules ovate to lanceolate, 0.2–0.25 × 0.1–0.15 mm, usually obscured by pubescence;

stolons: petiole 0.2–0.7 cm, blade obovate or elliptic to orbiculate, 0.6–2 × 0.5–1.1 cm, margins with distinct hydathodal teeth, base attenuate, surfaces densely hirtellous to glabrate;

stems: petiole 0–0.2(–1) cm, blade elliptic or lanceolate-elliptic to very narrowly elliptic, 1.5–8(–10) × 0.3–1.2(–1.4) cm, base cuneate or attenuate, margins entire with obscure hydathodal glands, apex acute or narrowly acute, surfaces ± densely hirtellous, leaves on branches much reduced;

bracts much reduced.

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.

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

bracteoles attached 1–2.2 mm distal to base of ovary, linear-lanceolate or narrowly elliptic, 3–6.5(–7.2)× 0.3–1.5(–1.7) mm, apex acuminate, surfaces hirtellous.

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 ascending with reflexed tips, pale green abaxially, creamy white adaxially, often tinged with pink or red, ovate-deltate, 3.5–5.5(–6) × 2–4 mm, margins entire, apex elongate-acuminate to subcuspidate, surfaces densely hirtellous;

petals 0;

filaments yellowish, 1.5–2.5 mm, base dilated, anthers 0.6–0.9(–1.3) × 0.5–0.7 mm;

pollen shed in tetrads;

ovary obovoid to cup-shaped, 2.5–4 × 2.5–4 mm;

nectary disc elevated 0.3–0.7 mm on ovary apex, bright yellow, turning black upon drying, 2–3.6 mm diam., indistinctly 4-lobed, densely hirtellous around style base and between lobes;

style cream, 1–2 mm, sparsely to densely hirtellous, especially proximally, stigma capitate, 0.3–0.6 × 0.3–0.6 mm, not 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.

subglobose or, sometimes, oblong-obovoid, subterete or with 4 rounded corners, 3–5 × 3–4.5 mm, hard-walled, irregularly dehiscent, pedicel 0–1 mm.

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

brown, elliptic-oblong or oblong-ovoid, slightly curved on both ends, 0.5–0.7 × 0.3–0.4 mm, surface cells ± isodiametric.

= 16.

= 32.