1. Elodea canadensis Michx.
Pl.
89 d–f; Map 337
Anacharis canadensis (Michx.) Planch.
Leaves variable, but those of the middle and upper stems 6–17 mm long, 1.2–4.5
mm wide. Staminate flowers on threadlike stalks 3–20 cm long reaching to the
water surface and remaining attached, the sepals 3.5–5.0 mm long, the petals
2.5–4.5 mm long, linear-lanceolate. Pistillate flowers on threadlike stalks
2–20 cm long reaching to the water surface, the sepals 2.2–2.7 mm long, the
petals 2.0–2.6 mm long, elliptic to spathulate. 2n=24, 48.
July–September.
Widely scattered in the Ozarks in primarily southern counties (U.S., Canada,
widely naturalized in Europe, Australia, and New Zealand). Submerged aquatic in
spring branches.
Elodea canadensis is commonly cultivated as an aquarium plant, and some
Missouri populations may represent escapes from cultivation.