ALLOPHYLLUS, in botany; a genus of the monogynia order, belonging to the octandria class of plants. The characters of which are: The calyx is a four-leaved perianthium, with orbicular leaflets, the opposite ones less: The corolla consists of four orbicular equal petals, less than the calyx; the claws broader, the length of the smaller leaves of the calyx: The stamina consist of eight slender filaments, the length of the corolla; the anthers are roundish: The pistillum has a round didymous germin above; the stylus is filiform, and longer than the stamina; and the stigma is bifid, with revolute divisions. There is but one species, the zeylanicus, a native of Ceylon.