Flora of North America species comparison

usually erect or strongly ascending, rarely floating or creeping, terete to somewhat angled on young branches, 30–250 cm, well branched to sparsely branched or simple, usually villous, often also strigillose, rarely glabrous, with raised lines decurrent from leaf axils.

prostrate, ascending or erect at tips, terete, well branched, 20–70 cm, glabrous or, sometimes, minutely strigillose on leaf margins and inflorescence.

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

petiole 0.2–3.5 cm;

blade broadly lanceolate, 3.5–18 × 1–4 cm, base narrowly cuneate, margins subentire, apex acuminate, surfaces hirsute or villous;

bracts slightly to much reduced.

opposite;

stipules narrowly deltate, 0.05–0.15 × 0.05–0.1 mm;

petiole narrowly winged, 0.2–0.8 cm, blades on submerged stems linear, 3.2–4.7 × 0.2–0.3 cm, those on emergent ones oblanceolate-elliptic to narrowly oblanceolate, (0.7–)1–1.7(–2) × 0.2–0.7(–1.1) cm, base very narrowly cuneate or attenuate, margins entire, apex acute;

bracts not reduced.

leafy racemes, flowers solitary in axils;

bracteoles often absent, when present, narrowly deltate, 2–3 × 1.2–2.4 mm, attached near ovary base.

sometimes few-flowered, erect racemes, flowers paired in leaf axils of prostrate stems;

bracteoles attached in opposite pairs at base of ovary or on pedicel distally, linear, 1–3(–4.5) × 0.1–0.7 mm, apex acuminate.

sepals ovate-deltate, 5.5–11 × 1.5–3 mm, margins entire, apex acuminate, surfaces villous;

petals orange-yellow, obovate, 5–11 × 4–8 mm;

stamens (8 or)10 or 12(or 14), in 2 unequal series, longer filaments 2.5–4.5 mm, shorter ones 1.5–2.5 mm, anthers oblong, 1.2–1.6 × 0.7–1 mm, extrorse;

ovary cylindric, subterete, 10–16 × 2–3 mm, glabrate to strigillose or villous;

nectary disc slightly elevated at ovary apex, 2–4 mm diam., lobed, depressed, surrounded by densely matted white hairs;

style 3–4.5 mm, glabrous, stigma capitate-globose, 1–1.5 × 2–2.5 mm, ± exserted beyond anthers.

sepals slightly reflexed at anthesis, ascending in fruit, light green, ovate-deltate or narrowly so, (3.5–)4–5(–6) × 1.7–3 mm, with 3 parallel veins, margins strigillose and finely serrulate, apex narrowly acute to elongate-acuminate, surfaces glabrous;

petals sometimes caducous, oblong-spatulate, 4.5–5.5 × 1.5–3 mm, base attenuate, apex obtuse;

filaments spreading, pale cream, 1.8–2.5 mm, anthers 0.7–1 × 0.5–0.7 mm;

pollen shed in very loose tetrads;

ovary obconic-cylindric, subterete or scarcely 4-angled, 3–5 × 2–2.5 mm;

nectary disc elevated 0.5–0.7 mm on ovary apex, bright yellow, 1.7–2.3 mm diam., 4-lobed, glabrate;

style cream, 1.1–1.7 mm, stigma cream, broadly capitate, 0.4–0.6 × 0.5–0.8 mm, often exserted beyond spreading stamens.

obscurely [4 or]5 or 6[or 7]-angled or subterete, straight or curved, 15–50 × 2.5–4 mm, relatively thin-walled, seeds visible as bumps, tardily and irregularly loculicidal, villous, pedicel 2–20 mm.

clavate, subterete to obscurely 4-angled, sometimes slightly curved, 6–10.5 × 2.5–4 mm, hard-walled, irregularly dehiscent, pedicel (4.5–)6–15(–20) mm.

in 1 row per locule, horizontal and loosely embedded in an easily detached horseshoe-shaped segment of firm endocarp, pale brown, obovoid, 1–1.2 mm, shiny, finely pitted, raphe much narrower than seed body.

light to dark brown, ellipsoid, 0.6–0.7 × 0.3–0.5 mm, surface cells transversely elongate.

= 32, 48.

= 48.