Flora of North America species comparison

often branched, to 3 m. Turions absent.

usually unbranched, to 6 m. Turions present, ± dark green, cylindrical, with gradual transition from foliage leaves to reduced turion leaves, 12–40(–45) × (3–)5–12(–15) mm, apex ± rounded;

leaves pectinate, stiff, strongly appressed to axis distally, not proximally, elliptic in outline, 5–15 × 1.4–5 mm, with clusters of brown, conical trichomes between leaf bases;

segments 13–15(–17), elongate botuliform, longest segment 1.8–5.2(–6) mm, basal segment usually less than or equal to 1/2 central axis of leaf, apex apiculate, with single, brown, conical trichome in each axil.

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.

in whorls of (3 or)4, heteromorphic;

petiole 0–4 mm; submersed leaves pectinate, usually obovate in outline, (2.8–)13–32(–44) × (2.1–)16–35 mm, segments 6–18(–24), linear-filiform, often perpendicular to central axis, basal segments often as long as leaf axis, segments often irregular in orientation, not parallel and not in same plane, longest segment 2–20(–26) mm; emersed leaves, basal sometimes pectinate to pinnatifid proximally, with abrupt transition to obovate, elliptic, sometimes distally spatulate, in outline, margins of distal leaves entire to serrate to shallowly lobed, 1–2.3 × 0.6–1(–1.5) mm.

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.

to 15 cm;

flowers proximally pistillate, medially bisexual, distally staminate;

bracteoles cream to stramineous or purple with distinct, reddish or brown margin, usually ovate to depressed-ovate, sometimes elliptic to triangular, (0.4–)0.6–1.3 × 0.3–0.7 mm, margins entire or serrate, sometimes with distal, irregular, membranous 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 to stramineous, usually depressed-ovate, sometimes ovate to triangular, 0.2–0.4 × 0.2–0.5 mm;

petals caducous, cream to red or dark purple, oblong to elliptic or obovate, 1.7–2.3(–3) × 1–2 mm;

stamens 8, filaments to 1.5 mm, anthers greenish cream to yellow or purple, 1–2.2 × 0.3–0.7 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 cream to green to purple, lanceolate to deltate or ovate, 0.1–0.3 × 0.1–0.2 mm;

petals often persistent, cream, widely ovate, 0.3–0.5 × 0.2–0.5 mm;

pistils 1–2 mm, stigmas white to red or ± purple, ± pulvinate, 0.2–0.4 mm.

cylindric to oblong, 4-lobed.

globose, 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.

olive-green to brown, cylindric to narrowly ovoid, 1.5–2.7 × 1.2–1.6 mm, transversely widely obovate, abaxial surface broadly rounded, sparsely and irregularly tuberculate, margins smooth or tuberculate, sometimes with 2 shallow, partial, longitudinal ridges, wings and ribs absent.

= 42.

= 42.