Ceratophyllum echinatum

Prickly Hornwort

SPINEY HORNWORT

NATIVE TO MAINE

Habitat: Prickly hornwort is found in the submersed plant community. It lacks true roots, and grows the best in quiet waters, generally preferring soft water with a low pH.

Description: Prickly hornwort is a submersed aquatic plant with coarse, bushy stems and no roots. The stiff leaves are fork-divided (generally forked three to four times), and arranged in whorls of 5 to 12 leaves. The leaves are smooth edged and hair-like (not serrated and flattened as is the case of close look-alike coontail), but small spines are sometimes present. Whorls of leaves are more closely spaced towards the end of branches giving the plant a raccoon tail appearance. Tiny flowers, followed by spiny fruits (on female plants only) are produced in the leaf axils. Prickly hornwort fruits have several spines of various lengths around the outer edge and a rough surface. (The fruits of coontail are smooth and have two spines at the base.)

Origin and Range: Prickly hornwort is native to New England and much of the US. Of the two Ceratophyllum species found in Maine: coontail and prickly hornwort, coontail occurs more frequently.

Annual Cycle: Because prickly hornwort is tolerant to low light and cool water, it is able to overwinter under the ice as an evergreen plant. Photosynthesis and growth slow during the winter months and resume with vigor in the spring. Male and female flowers occur on separate plants, making fertilization and seed production unreliable. Reproduction occurs mainly through plant fragmentation.

Value in the Aquatic Community: Because coontail overwinters as an evergreen plant, it provides important habitat to many invertebrates and fish year round. Waterfowl feed upon both foliage and fruit.

Look Alikes: coontail, variable leaf water-milfoil and species of the water-milfoil genus.