Flora of North America species comparison

absent.

often branched, to 3 m. Turions absent.

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

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.

mostly in whorls of (3 or)4(or 5), sometimes opposite to subopposite, heteromorphic;

petiole 0–4 mm; submersed leaves pectinate to lobed (basalmost leaves opposite to subopposite, reduced, margins entire), ovate to obovate in outline, (3–)5–25(–35) × (2–)3–18(–20) mm, segments (2 or)3–9(–11), linear, ± applanate, longest segment (7–)8–15(–17) mm; emersed leaves pinnatisect to lobed or entire, ovate to oblong in outline, 2–9 × 1–6 mm, margins dentate to minutely serrate.

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.

to 8 cm;

flowers proximally pistillate, medially bisexual, distally staminate;

bracteoles cream, deltate, 0.5–1 × 0.2–0.6 mm, margins dentate to serrate, with glandular tip.

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.

sepals green to cream, ovate to deltate, (0.2–)0.3–0.5(–0.7) × (0.1–)0.2–0.4(–0.5) mm;

petals persistent, ± purple, oblong, 2–3 × 0.5–1.5 mm;

stamens 8, filaments to 0.6 mm, anthers 1.8–2.5 × 0.2–0.6 mm.

sepals cream, deltate, 0.2–0.5 × 0.1–0.4 mm;

petals ± persistent, cream, ± cucullate, elliptic, 0.1–0.5 × 0.2–0.3 mm;

pistils 1.1–2.2 mm, stigmas cream to ± purple, to 0.6 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 oblong, 4-lobed.

cylindric to subglobose, deeply 4-lobed.

tan to olive-brown, cylindric to ovoid, 1.5–1.8 × 0.6–0.8 mm, transversely elliptic, abaxial surface rounded, smooth, sometimes with a shallow, longitudinal ridge, wings and ribs absent.

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.

= 42.

= 14.