Cabomba caroliniana Gray: Fanwort. Cabombaceae (water-shield family).
Native perennial. Rooted submersed plant with many long, branched, flexible, spongy stems and dense, feathery foliage; it occurs in 3 - 10 ft (0.9 - 3 m) of water. The stem has pairs of finely-cut, pom-pom-like leaves at each node. The leaf stalk is flexible and gives rise to a leaf blade consisting of numerous narrow, flat divisions that branch several times. The ends of these divisions are blunt or squared-off; the leaf forms a characteristic fan-shaped semi-circle when it is spread out flat. Leaves may have purple or reddish coloration on the underside. Flowers are white to pale purple, about 0.5 in (1.25 cm) wide, and are borne at or a little above the water surface; they may be accompanied by small, narrow, diamond-shaped leaves whose stalks are attached in the center of the lower surface as in the related watershield, Brasenia schreberi. Fanwort's dense structure can cause access and water flow problems where population numbers are high.
