Flora of North America species comparison

often branched, to 1.5 m.

absent.

usually in whorls of 4(–6), sometimes subverticillate, heteromorphic;

petiole to 3 mm; submersed leaves pectinate, obovate in outline, (12–)16–30(–41) × (10) 12–22(–30) mm, segments 12–24, linear-filiform, longest segment (6–)9–25(–36) mm; emersed leaves pectinate to pinnatifid proximally, linear to narrowly oblong or linear-lanceolate distally, (5–)7–16(–23) × (0.5–)1–2.2(–2.6) mm, often increasing in size distally, segments (5–)10–16(–22), 0–2.5 mm, margins serrate to shallowly lobed.

to 35 cm;

flowers proximally pistillate, medially bisexual, distally staminate;

bracteoles cream, ovate to triangular, (0.4–)0.7–1 × 0.2–0.7 mm, margins irregularly lobed.

sepals cream, trullate to lanceolate, (0.1–)0.2–0.4(–0.5) × 0.1–0.4(–0.5) mm;

petals persistent, cream to pink, elliptic to ovate, 1–1.5 ×0.5–0.8(–0.9) mm;

stamens 4, filaments to 1 mm, anthers 0.5–0.9 × 0.2–0.4 mm.

sepals cream, trullate to lanceolate, 0.2–0.4 × 0.1–0.2 mm;

petals persistent, cream to pink, elliptic to ovate, 0.7–1.3 × 0.4–0.7 mm;

pistils 1.1–1.5 mm, stigmas red to ± purple, to 0.4 mm.

cylindric to subglobose, cruciate to deeply 4-lobed.

tan to light green to red-brown or purple, cylindric to narrowly ovoid, 1.1–1.5 × 0.4–0.6 mm, transversely elliptic to narrowly ovate, compressed to flattened, abaxial surface bluntly 2-angled, flattened to slightly rounded, papillate to tuberculate, with 2(or 4) shallow, longitudinal ridges, wings and ribs absent.