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, slightly ridged, usually well branched, 10–80(–100) cm, glabrate or often with strigillose raised lines decurrent from leaf axils.

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-triangular, 0.15–0.35 × 0.05–0.25 mm, succulent;

stolons: petiole attenuate, 0.3–1 cm, blade narrowly elliptic, 1.5–3.5(–5.5) × 0.5–1.3(–2) cm;

main stem: petiole 0–1.5 cm, blade usually narrowly elliptic to elliptic, sometimes linear, 3–12 × 0.3–2.1 cm, base attenuate, margins subentire with hydathodal glands often visible, apex acute to very narrowly acute, surfaces densely papillose-strigillose, abaxial veins glabrous or sparingly, minutely strigillose;

leaves on side branches usually reduced, 0.8–4.5 ×0.2–1 cm;

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.

open, leafy racemes or spikes, flowers solitary in axils, often congested, especially on branches;

bracteoles attached on pedicel at base of ovary or to 2 mm distal to base, narrowly lanceolate to sublinear, 0.4–1 × 0.1–0.4 mm, apex acuminate, surfaces glabrate.

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, light green, ovate-deltate, 1.1–2.3 × 1–1.8 mm, margins entire, fringed with minute, strigillose hairs, apex short-acuminate or acute, surfaces glabrous;

petals 0;

filaments nearly translucent, 0.6–1.1 mm, anthers 0.3–0.5 × 0.3–0.6 mm;

pollen shed in tetrads;

ovary subcylindric, 2–5 × 0.8–1.9 mm;

nectary disc elevated 0.3–0.4 mm on ovary apex, light green, 0.6–1.8 mm diam., 4-lobed, glabrous or minutely papillose;

style pale green, 0.3–0.8 mm, glabrous, stigma broadly clavate to subglobose, 0.2–0.5 × 0.2–0.5 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.

subcylindric, subterete to obscurely 4-angled with 4 shallow grooves, 2–8(–9) × 1.3–2(–3) mm, hard-walled, irregularly dehiscent, pedicel 0–0.3(–0.5) mm.

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

light brown, kidney-shaped with slightly pointed ends, 0.5–0.8 × 0.3–0.4 mm, surface cells columnar, elongate either parallel or transversely to seed length.

= 16.

= 32.