Habitat: Maine is home to two native waterweed species: common[waterweed (Elodea canadensis) and slender waterweed (Elodeanuttallii). Both are found in the submersed plant community. Preferring fine, nutrient-rich sediment, the plants grow to depths of[several meters. (Waterweeds may be found in a wide range of[environments, including freshwater ponds, slow moving streams or[tidal tributaries.)
Description: Common waterweed and slender waterweed share[many common characteristics and it may not always be easy to distinguish between the two. Both have slender stems supporting small, lance-shaped leaves. The stems, anchored to the sediments by[shallow roots, grow up to one meter long, often branching profuselyand forming dense, tangled stands. The leaves are attached directly to the stem (no petiole) in whorls, with precisely three leaves per whorl. (For both of these species, it would be considered rare to find a whorl of leaves that contained any number other than three.) The leaf edges of both species are finely serrated, visible only with significant magnification. Both species produce small, white flowers with three petals at the tips of long slender stalks and rise to (or above) the water surface at maturity. Female flowers are most often seen; male flowers are rarely produced. The shape, texture, and proportions of the leaves provide the best means for distinguishing between the two native waterweeds. The relatively firm leaves of common waterweed tend to be shorter, stouter (averaging 2 mm in width), and relatively blunt at the tip. The leaves of slender waterweed are typically longer, more flimsy and slender (averaging 1.3 mm in width), and more sharply pointed at the tip. Also, the leaves of common waterweed tend to get more densely crowded toward the tip then those of slender waterweed. Maine’s native waterweeds rarely have more than three leaves per whorl which helps to distinguish them from their invasive look alikes: hydrilla and Brazilian waterweed. Both of these invaders typically have four or more leaves per whorl. |
