Ceratophyllum demersum L.: Coontail, hornwort. Ceratophyllaceae (hornwort family).
Native perennial. This plant grows submersed in slow-moving water; it does not attach firmly in the substrate as it lacks true roots. It is able to colonize water to 18 ft (5.5 m) deep. The light-colored stems are slender and brittle and they branch freely, although branches are limited to one per node. Plants multiply vegetatively when broken pieces of stem grow to whole plants. The stalkless leaves occur in brush-like whorls of as many as 12; they can be up to 1.25 in (3 cm) long. Individual leaves consist of very slender segments that fork one or more times; these segments have pointed ends and toothed edges that make the leaves feel rough. The rather stiff leaves curve in toward the stem when removed from the water but do not flatten or collapse completely. The denser arrangement of leaf whorls near the tips makes the stems resemble bushy raccoon or fox tails, particularly when the wet plant is held tip-down. Inconspicuous flowers emerge at nodes. The long-branched stems provide wildlife habitat, but the plants can aggregate to form areas of dense matted growth, and the plant sometimes becomes a nuisance to a range of water uses.
