BLADDER-NUT, in botany: A genus of plants belonging to the clas of pentandra, and order of trigynia; and in the natural system arranged under the 23rd order, tribilata. The calyx is quinquepartite. There are five petals. The capsules are three, inflated and joined together by a longitudinal suture. The seeds are two, and are globose with a scar. There are two species, the pinnata and triflora. The pinnata, or bladder-nut-tree, is a tall shrub or tree. The leaves are pinnated; the pinnae are generally five, oblong, pointed, and notched round the edges. The flowers are white, and grow in whorls on long pendulous footstalks. This plant flowers in June, and is frequent in hedges about Pontefract and in Kent. The triflora, or three-leaved bladder-nut, is a native of Virginia.