The Bullrushes (_Typha_), also called Cat’s-tail and Reed-mare, are tall rush-like plants, with a cylindrical mass of dark brown flowers round the stem, surmounted by a spike of yellow flowers. The lower dark-brown flowers are female ones, and the yellow ones are the males; the former consist only of an ovary on a long stalk, and a calyx cut into fine hairs so as to form a kind of pappus. The male flowers have a chaff-like calyx, enclosing the stamens, the filaments of which are united at the base, and the anthers are very long and of a bright yellow. The seed is a dry capsule, and the plant has a rhizoma or creeping stem under the water. ORDER CCIV.—AROIDEÆ.—THE ARUM TRIBE. These curious plants have their flowers in a spadix, enclosed in a spathe, the male and female flowers being separate, and the former above the latter, with some abortive ovaries again above them. The male flowers have only one stamen in each without any covering; and the female flowers in like manner consist each of a single ovary, with a puckered-up hole in the upper part, which serves as the stigma. The fruit consists of a cluster of red berries, which form round the spadix. Many of these plants have a very unpleasant smell, and some of them have a tuberous root, which, when cooked, is eaten, though it is poisonous when raw. _Arum_ or _Caladium esculentum_ is thus eaten as a common article of food in the East Indies; but the Dumb Cane (_A._ or _C. seguinum_) has its English name from its juice being so poisonous as, if tasted, to cause the lips to swell so as to prevent the possibility of speaking. The beautiful marsh plant called _Calla_ or _Richardia ethiopica_, or the White Arum, belongs to this order; as does the fragrant rush, _Acorus Calamus_. The order Typhaceæ is included by many botanists in Aroideæ; and indeed, the difference between them consists principally in the Bullrushes having no spathe. ORDER CCV.—FLUVIALES, OR NAIADES.—THE POND-WEED TRIBE.