Flora of North America species comparison

absent.

delicate, often branched, to 1 m, with numerous black, ascidiate trichomes.

often branched, to 1.5 m. Turions absent.

present, green to brown, very narrowly cylindrical, with gradual and moderate transition from foliage leaves to slightly reduced turion leaves, to 10 cm, apex ± rounded;

leaves pectinate and stiff, strongly appressed to axis, elliptic to narrowly obovate in outline, 11–23(–40) × 1.5–3(–4) mm;

segments 6–12(–14), longest segment (1.5–)3–5.5 mm, basal segment less than or equal to 2/3 central axis of leaf, apex acute; brown, ascidiate trichomes scattered on surfaces and in axils.

all submersed, usually in whorls of 3(or 4), sometimes alternate or subverticillate, homomorphic;

petiole 0–3 mm;

leaves pectinate, ovate to elliptic or obovate in outline, (6–)10–20(–25) × (4–)7–15 mm, segments (7–)10–14(–16), linear-filiform, longest segment (4–)8–15(–22) mm, with black ascidiate trichomes scattered on surfaces and in axils.

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.

submersed, to 30 cm;

flowers bisexual;

bracteoles cream, trullate, 0.2–0.5(–0.8) × (0.1–)0.3–0.5 mm, margins entire or irregularly lobed, lobes with glandular fringe.

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.

sepals green to cream or ± purple, ovate to trullate, 0.1–0.5(–0.7) × 0.1–0.3(–0.5) mm;

petals persistent, cream to purple, elliptic to obovate, 0.6–1.3 × 0.3–0.8 mm;

stamens 4, filaments to 0.5 mm, anthers 0.2–0.4 × 0.1–0.3 mm;

pistils 0.8–1.2 × 0.2–0.3 mm, stigmas red to ± purple, to 0.5 mm.

cylindric to subglobose, deeply 4-lobed.

cylindric to subglobose, cruciate to deeply 4-lobed.

tan to brown, cylindric, (1–)1.5–2.5 × 0.5–0.9 mm, transversely hexagonal (rounded to obtusely angled adaxially), abaxial surface shallowly 4-angled, smooth or sparsely tuberculate, with 4 longitudinal ridges, ridges with irregular, shallow to pronounced, membranous wings, ribs absent.

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.

= 14.