Flora of North America species comparison

erect, 4-angled, rarely 4-winged, sometimes basally terete, 40–280 cm, simple to densely branched, branches often ascending, glabrous.

prostrate or decumbent and ascending at tips, slightly ridged, often well branched, 5–70 cm, glabrate to sparsely strigillose, denser on distal parts.

stipules deltate, 0.2–0.3 × 0.15–0.2 mm;

petiole 0.2–2.2 cm, somewhat flattened and continuous with ridges or wings on stem;

blade elliptic to narrowly lanceolate, 2–20 × 0.2–4 cm, base cuneate, margins minutely scabrid, apex acute or acuminate, membranous, surfaces glabrous or sometimes minutely strigillose along abaxial veins;

bracts often reduced.

opposite;

stipules narrowly deltate or ovate, 0.05–0.15 × 0.05–0.1 mm; submerged stems: petiole 0–0.2 cm, blade narrowly linear, 1.9–4 ×0.1–0.25 cm;

emergent stems: petiole 0–0.2 cm, blade narrowly elliptic or narrowly oblanceolate-elliptic to linear, 0.6–1.8 × 0.2–0.5 cm, base narrowly cuneate, margins entire, apex acute, surfaces glabrous or sparingly strigillose on margins and abaxial midveins;

bracts reduced.

leafy spikes, flowers solitary in distal axils;

bracteoles attached at base of ovary or on lower 1/2, without subtending glands, deltate, 0.3–0.5 × 0.2–0.3 mm, apex acute.

in racemes or spikes, well-formed on ascending stems, not on prostrate stems;

bracteoles attached at base of ovary or 1.5–8 mm proximally on pedicels, sublinear to very narrowly elliptic, 1.4–5 × 0.2–0.8 mm, apex acute, surfaces minutely strigillose.

sepals ovate or lanceolate, 3–6 × 1–2 mm, apex acute or short-acuminate, surfaces usually glabrous, sometimes strigillose;

petals obovate, 3.5–5 × 2–2.5 mm;

stamens 8 in 2 subequal series, filaments 1.3–1.5 mm, anthers oblong, 0.6–1 × 0.4–0.5 mm;

ovary obconic, 4-angled, 4–10 × 2–4 mm, usually glabrous, rarely strigillose;

nectary disc plane on ovary apex, 3–4 mm diam., 4-lobed, glabrate;

style 0.5–1.5 × 0.5–0.6 mm, stigma globose, 0.8–1 × 1–1.2 mm, not exserted beyond anthers and pollen shed directly on it.

sepals reflexed or spreading, green, lanceolate-deltate, 5.2–10 ×1.5–2.7 mm, with 3 prominent parallel veins, margins entire and minutely strigillose, apex acute or elongate-acuminate, surfaces minutely strigillose abaxially;

petals rarely caducous, elliptic-obovate to spatulate-obovate, 7–11 × 4.5–8 mm, base attenuate, apex rounded;

filaments initially spreading, becoming erect, yellow, 2.5–4.5 mm, anthers 1.3–2 × 0.7–1.1 mm;

pollen shed in tight tetrads;

ovary cylindric to funnelform, 4–5.5 × 1.5–2.8 mm;

nectary disc elevated 0.6–1 mm on ovary apex, 1.5–2.6 mm diam., bright yellow, with 4 distinct domed lobes, minutely strigillose between lobes or glabrous;

style yellow, 2.3–4(–4.8) mm, glabrous, stigma yellow, broadly capitate, 0.3–0.6 × 0.6–1.8 mm, as long as or exserted beyond anthers.

oblong-linear to squarish-cylindric, 4-angled, 10–22 × 2–4 mm, thin-walled, irregularly dehiscent, subsessile.

clavate, subterete, sometimes slightly curved, 5.5–10 × 2.3–4 mm, hard-walled, irregularly dehiscent, pedicel (12–)17–45 mm.

elongate-ovoid, 0.3–0.5 × 0.2–0.3 mm, raphevery reduced and inconspicuous.

light to dark brown, elliptic-oblong, 0.5–0.7 × 0.3–0.4 mm, surface cells transversely elongate.

= 16.

= 32.