BUR-REED, in botany: A genus of plants belonging to the class of monocotyledons, and to the order of triandria; and in the natural system ranged under the 3rd order, Calamaria. The amentum of the male male flower is roundish, the calyx is triphyllous, and there is no corolla. The amentum of the female flower resembles that of the male. The stigma is bifid; the fruit is a dry berry containing one seed. There are two species, the erectum and natans, both of them natives of Great Britain and Ireland. 1. The *Erethrum*, great bur-reed, has a stem two or three feet high, erect, firm and branched; the lower leaves are triangular, the upper ones plain. The male heads are much smaller than the female. This species flowers in July, and is frequent on the banks of rivers and lakes and near stagnant waters. 2. The *Natans*, floating or little bur-reed, has a stalk about two feet long. The leaves float, are about a foot long, one-fourth of an inch wide at the base, and one-eighth in the middle, and end in a point. The male spicules are generally three, and all fertile; the female are commonly three, the two lower being supported on peduncles, the uppermost fertile. It flowers in July, and grows in pools and lakes, but is rare.