Flora of North America species comparison

present.

absent.

terete to flattened, without spots, to 150 cm;

nodal glands absent.

terete, without spots, 2–5 cm;

glands absent.

absent.

common, axillary, 0.5–2 cm × 0.5–1.2 mm, soft;

leaves ± 2-ranked;

outer leaves 2–3 per side, base not corrugate, apex acute;

inner leaves undifferentiated or rolled into tight, hardened structure.

both submersed and floating or submersed only, ± spirally arranged.

submersed, or both submersed and floating, ± spirally arranged.

petioles continuous in color to apex, 3–4.5 cm;

blade yellow-green to dark green, elliptic to ovate, 3.5–4 cm × 16–20 mm, base rounded, apex acuminate;

veins 11–13.

petioles continuous in color to apex, 5–25 mm;

blade adaxially greenish brown, elliptic, spatulate, or obovate, 0.6–1.5 cm × 3–8 mm, base acute, apex obtuse;

veins 5–9.

sessile or rarely petiolate, lax;

stipules persistent, inconspicuous, convolute, free from blade, pale green to brown, not ligulate, 1.3–1.6 cm, not fibrous, not shredding at tip, apex acute to obtuse;

petioles to 3 cm;

blade light green to brownish green, elliptic, not arcuate, 3.1–9.1 cm × 3–27 mm, base attenuate, without basal lobes, not clasping, margins entire, rarely crispate, apex not hoodlike, acuminate, lacunae in 1–2 rows each side of midvein;

veins 3–9.

sessile, delicate;

stipules persistent, inconspicuous, convolute, free from blade, green to brown, not ligulate, 0.4–1.2 cm, not fibrous, not shredding at tip, apex attenuate;

blade light green, linear-filiform, not arcuate, 2–8 cm × 0.1–1 mm, bases slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, acute to almost bristle-tipped, lacunae present, rarely absent, 0–2 rows each side of midvein;

veins 1(–3).

emersed, unbranched;

peduncles not dimorphic, both axillary and terminal, erect to ascending, cylindric, 3.2–7.7 cm;

spikes not dimorphic, cylindric, 15–35 mm.

unbranched, emersed;

peduncles not dimorphic, terminal, ascending in flower, recurved in fruit, cylindric, 5–30 mm;

spikes not dimorphic, cylindric or moniliform, 6–8 mm.

sessile, greenish brown, ovoid, laterally compressed, abaxially and laterally keeled, 1.9–2.3 × 1.8–2 mm, lateral keels without points;

beak erect, 0.3–0.5 mm;

sides without basal tubercles;

embryo with less than 1 full spiral.

sessile, green to brown, obliquely round-obovoid, compressed, abaxially keeled, not laterally keeled, 1.5–2.5 × 1.2–1.6 mm;

beak erect, 0.3–0.5 mm;

sides without basal tubercles;

embryo with 1 full spiral.

= 52.

= 28.