Flora of North America species comparison

absent.

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

branched or unbranched, to 3 m. Turions present, becoming brown to red-brown at maturity, clavate to obdeltoid, with abrupt transition from foliage leaves to reduced turion leaves, (6–)11–37(–52) × (3–)4–6(–9) mm, apex ± rounded, lateral turions with several whorls of minute, brown prophylls, entire proximallyand toothed to lobed distally, ovate to elliptic or lanceolate in outline;

leaves pectinate, strongly appressed to axis throughout, narrowly flabelliform in outline, 4.5–7.5 × 1.2–1.8(–4) mm;

segments 8–12(–18), flattened, linear-lanceolate, longest segment 1.5–6 mm, basal segment usually greater than or equal to 2/3 central axis of leaf, apex ± acute, trichomes usually 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.

in whorls of (3 or)4, heteromorphic;

petiole to 6 mm; submersed leaves pectinate, ovate to elliptic in outline, (7–)12–30(–46) × 9–24(–40) mm, segments (9–)12–22(–34), linear-filiform, longest segment (2–)6–19(–29) mm; emersed leaves pectinate, lanceolate to elliptic to ovate in outline, 2–5(–15) ×0.9–2.6 mm, segments (9–)12–20, greater than 0.5 mm.

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 25 cm;

flowers proximally pistillate, medially bisexual, distally staminate, in whorls of 4;

bracteoles cream, ovate, 0.3–0.6(–1) × 0.1–0.6(–1.3) mm, margins deeply dissected into irregular lobes.

sepals cream, narrowly triangular to deltate, 0.5–0.7(–0.9) × 0.4–0.6(–0.8) mm;

petals persistent, cream, sometimes apically suffused with purple, elliptic to obovate, 1.8–2.2(–2.4) ×0.7–1.5 mm;

stamens 8, filaments to 2 mm, anthers 0.8–1.7 × 0.3–0.6 mm.

sepals greenish to cream, elliptic to triangular, 0.2–0.7 × 0.2–0.7 mm;

petals often caducous, sometimes persistent, cream to purple, elliptic to obovate, 0.4–0.7(–0.9) × 0.3–0.5(–0.8) mm;

pistils (1.3–)1.8–2.7 mm, stigmas red to± purple, to 0.8 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.

globose, shallowly 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.

olive-green to brown, subglobose to globose, 2–2.7(–3) × (0.9–)1.1–1.3(–1.7) mm, transverselywidely obovate, abaxial surface broadly rounded to moderately flattened, smooth, often with 2 shallow longitudinal ridges, wings and ribs absent.

= 14.

= 28.