Najas guadalupensis (Spreng.) Magnus
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Monoecious; stems profusely branched, 1–8 dm; lvs 0.5–3 cm × 0.2–2 mm, spreading, not so sharply pointed as in our other spp., with sloping shoulders at the base, minutely serrulate with 20–100 unicellular teeth per side; anthers dithecal, with 4 microsporangia; style apical; seeds 1.2–2.5 mm, purple-tinged, fusiform, pitted, the areolae 4–6-angled, about as long (0.08–0.1 mm) as wide, in 20–40 rows; 2n=12, 36, 48, 54, 60. Widespread in N. and S. Amer., n. to Me., s. Que., Man., Alta., and Wash. The widespread var. guadalupensis, slender, with stems 0.2–1 mm thick, and with 50–100 teeth on each side of the lf, tends to give way at the n. to var. olivacea (Rosend. & Butters) R. R. Haynes, which occurs from N.Y. and s. Que. to n. Ind., n. Io., and s. Man., and is stouter, with stems mostly 1–2 mm thick, and with 20–40 teeth per side of the lf. (N. olivacea)