Common waterweed – Egeria densa
Egeria densa is not native to Florida. The exotic Egeria is also known as Brazilian elodea. However, Egeria is Egeria; not Elodea, which is another plant altogether. This submersed plant is rooted, but pieces of it may be found drifting in the water. Egeria occurs in streams, ponds, and lakes of Florida. The slender stems of Egeria are usually a foot or two long, but can be much longer. The small leaves are strap-shaped, about an inch long, and one-quarter-inch wide. The leaf margins have very fine saw teeth that require a magnifying lens to see. Leaves occur in whorls of three to six, around the stem. The whorls grow from regularly spaced nodes that become more profuse toward the tip of the stem. Egeria flowers are on short stalks, about an inch above the water. They have three white petals that can be up to three-quarters of an inch across. Egeria can be easily confused with another exotic submersed plant in Florida, Hydrilla. The easiest way to distinguish between these two is by flower size and the underside midrib of the leaf. Hydrilla’s female flowers are white and very small. They grow to the surface of the water on long, very thin flower stalks. Egeria’s white flowers, however, are much larger and more conspicuous. They can be up to three-quarters of an inch across. The leaves of Hydrilla have one or more teeth on the underside midribs; Egeria, on the other hand, never has teeth on the underside midrib. Hydrilla produces tubers and turions; Egeria does not. Remember, the exotic Egeria
- has a long stem with strap-shaped leaves.
- leaves are in whorls of three to six, with finely serrated margins.
- Egeria flowers are white and up to three-quarters of an inch wide.
Egeria densa may be confused with
Line-drawing comparison of hydrilla, elodea, and common waterweed
Hydrilla verticillata or Elodea canadensis