Flora of North America species comparison

erect or ascending to creeping or floating, terete or sometimes angled distally, 20–300(–450) cm, usually densely branched, sometimes simple, glabrous if floating, or densely villous and viscid throughout, or rarely just on inflorescence.

usually erect or ascending, rarely prostrate, slightly to distinctly winged, wings to 1.8 mm wide, unbranched to densely branched, 5–60 cm, glabrous.

stipules (rarely in clusters of 3), ovate-deltate, 0.6–2 × 0.6–1.5 mm, fleshy, apex subacute, often mucronate;

petiole 0.1–1.1 cm;

blade usually lanceolate to (narrowly) elliptic or oblanceolate, rarely narrowly obovate, (1.7–)3.1–8(–10.5) × 0.5–2(–2.5) cm, chartaceous, viscid, base cuneate or attenuate, margins entire, apex obtuse or acute, always glandular-mucronate, surfaces densely villous, sometimes less dense adaxially, distal leaves more pubescent than proximal ones;

bracts scarcely reduced.

alternate;

stipules lanceolate-deltate, 0.13–0.15 × 0.1–0.13 mm;

stolons: petiole attenuate, 0.1–0.5 cm, blade broadly elliptic to suborbiculate, 0.2–0.7 × 0.2–0.5 cm;

stems: petiole winged, 0.1–0.5 cm, blade obovate-spatulate or oblanceolate, sometimes narrowly oblanceolate-elliptic, 0.4–1.7 × 0.15–1 cm, base attenuate, margins subentire or often with hydathodal glands forming minute teeth, or minutely papillose-strigillose, apex acute or mucronate, surfaces glabrous;

leaves on side branches much reduced, glabrous;

bracts near apex and on branches reduced.

on emergent stems sometimes in leafy racemes, flowers solitary in leaf axils;

bracteoles narrowly to broadly obovate, 1–1.2 × 0.7–0.8 mm, succulent, apex acute, oppositely attached at ovary base.

leafy spikes or racemes, flowers solitary in axils, usually not crowded;

bracteoles attached at base of ovary, sublinear or narrowly oblong, 0.4–1.2(–1.5) × 0.1–0.4 mm, usually with swollen base.

sepals usually deciduous, not persistent on capsule, lanceolate, 6–12(–16) × 2–4 mm, chartaceous, apex acute, surfaces densely villous;

petals yellow, fan-shaped, (12–)16–20(–26) × 11–16(–21) mm, apex rounded, usually emarginate, rarely mucronate;

stamens 10(or 12), in 2 unequal series, yellow, filaments reflexed, shorter ones (2.8–)3.8–5.3 mm, longer ones (3.7–)6–6.5 mm, anthers oblong, 1–2.5 × (0.6–)0.8–1.2 mm;

ovary subcylindric, terete, 6–12 × 1.5–2.5 mm, apex thickened, densely villous;

nectary disc slightly raised on ovary apex, yellow, 1.5–2.5 mm diam., lobed, ringed with villous hairs;

style yellow, 4.7–6.7(–8) mm, glabrous or sparsely pubescent near base, stigma subcapitate-globose, 1–1.3 × 1.6–2.5 mm, usually exserted beyond anthers.

sepals ascending or spreading, pale green to cream adaxially, ovate-deltate, 0.9–2 × 1–1.9 mm, margins minutely papillose-strigillose or entire, apex acuminate, surfaces glabrous;

petals 0;

filaments translucent, 0.4–0.55 mm, anthers 0.1–0.2 × 0.2–0.3 mm;

pollen shed singly;

ovary pale green, obovoid-subglobose, 0.8–1 × 0.8–1.2 mm, glabrate;

nectary disc nearly flat on ovary apex, light green, 0.5–1.2 mm diam., 4-lobed, glabrous;

style light green, 0.3–0.6 mm, glabrous, stigma subcapitate, 0.15–0.3 × 0.05–0.15 mm, not exserted beyond anthers.

subcylindric, terete, straight or curved, (11–)14–25 × 3–4 mm, with thick woody walls, irregularly and tardily dehiscent, villous-viscid, pedicel 13–25(–27) mm.

obconic, subterete, 1–1.5 × 1.4–1.9 mm, thin-walled, seeds often visible as bumps, dehiscent by apical ring, pedicel 0–0.2 mm.

embedded in wedge-shaped piece of endocarp, 0.8–1 × 0.8–0.9 mm.

dark reddish brown, oblong-ovoid, 0.5–0.6 × 0.3–0.4 mm, surface cells transversely elongate, glabrous or, sometimes, densely covered by waxy hairs.

= 48.

= 16.