Flora of North America species comparison

floating or creeping and ascending to erect, terete, 20–200(–400) cm, simple to densely branched apically, glabrous (floating) or sparsely to densely villous (emergent), sometimes villous only on inflorescence.

erect, slightly ridged, unbranched or slightly branched, (16–)30–90 cm, glabrous or strigillose to hirtellous, especially on distal parts.

stipules ovate or deltate, 0.7–2 × 0.5–1.1 mm, not succulent, apex subacute, mucronate;

petiole flattened, 0.5–2(–2.5) cm;

blade narrowly oblanceolate, narrowly elliptic, or lanceolate to obovate or spatulate, (1.5–)4.2–10.7(–13.5) × (0.5–)0.8–3 cm, chartaceous, base cuneate or attenuate, margins entire, apex acute to obtuse, rounded or truncate, sometimes mucronate, surfaces not shiny, usually glabrous, sometimes villous on petiole and veins or throughout;

bracts not reduced.

alternate;

stipules deltate, 0.25–0.45 × 0.15–0.4 mm;

rhizomes: sessile, blades minute, appressed, and scalelike, oblate or suborbiculate, 0.3–0.6 × 0.6–0.9 mm;

stolons: petiole 0.1–0.6 cm, blade oblong or oblanceolate-elliptic to spatulate, 0.4–3.5 × 0.2–1.5 cm;

main stem: sessile, blade lanceolate-elliptic or lanceolate-linear to linear, 2.5–9.5 × (0.1–)0.3–0.9 cm, proximal ones shorter and often oblong or oblong-lanceolate, base rounded or obtuse, margins entire with obscure hydathodal glands, apex acuminate to acute, surfaces glabrous or, sometimes, pilose on proximal blades;

bracts very reduced.

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

bracteoles obovate to narrowly obovate, 1–1.8 × 0.7–0.8 mm, apex acute or acuminate, attached on distal 1/2 of pedicel or at ovary base.

densely clustered, terminal racemes or spikes, 1–5(–12) cm;

bracteoles attached at base of ovary or on pedicel distally, narrowly lanceolate, 3.5–5(–6) × (1.2–)1.4–2 mm, surfaces usually glabrous, sometimes pilose abaxially.

sepals ovate-deltate or lanceolate-deltate, (8–)12–19 × 2–5 mm, chartaceous, margins entire, apex acuminate, surfaces ± densely villous;

petals bright yellow, sometimes with orange base, fan-shaped, (15–)20–30 × (12–)16–25 mm, apex emarginate or mucronate;

stamens 10(or 12), in 2 unequal series, yellow, filaments recurved, shorter ones (1.6–)2.3–5.2 mm, longer ones (3.1–)3.6–7.5 mm, anthers oblong, (1.2–)1.7–4 × 1–1.5 mm;

ovary subcylindric, terete, 10–18 × 2–3 mm, apex ± broadened, glabrous or sparsely to densely villous;

nectary disc slightly raised on ovary apex, yellowish green, 2–4 mm diam., lobed, glabrous or ringed with white hairs;

style yellow, 6–10 mm, glabrous, stigma subcapitate-globose, 0.5–1.5 × 1.5–2.5 mm, often exserted beyond anthers.

sepals ascending, pale green or white adaxially, broadly ovate-deltate, 2.3–3.5(–4) × 2.3–3.2(–3.8) mm, margins entire, apex acuminate, surfaces glabrous;

petals 0;

filaments yellow or cream, 1.2–2 mm, distinctly dilated toward base, anthers 0.7–1(–1.3) × 0.5–0.7 mm;

pollen shed in tetrads;

ovary broadly obovoid or cup-shaped, 2.2–3 × 2.3–3.3 mm;

nectary disc elevated 0.5–0.6 mm on ovary apex, pale yellow, 1.8–3.1 mm diam., obscurely 4-lobed, glabrous;

style pale yellow, 0.9–1.7 mm, glabrous, stigma pale green to white, globose to capitate, 0.4–0.8 × 0.5–0.8 mm, distinctly 4-lobed, not exserted beyond anthers.

cylindric or subclavate, terete, sometimes curved, (12–)16–24(–30)× 2.5–4 mm, with thick woody walls, irregularly and tardily dehiscent, pedicel (9–)13–25(–85) mm.

broadly obpyramidal, angles rounded, sometimes subspherical, 2.5–4.3 ×2.5–4.5(–5) mm, hard-walled, dehiscent by apical ring, pedicel 0.5–1.5(–2) mm.

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

brown, elliptic-oblong, curved on both ends, 0.5–0.6 × 0.2–0.3 mm, surface cells ± isodiametric.

= 80.

= 32.