CARYO'CAR, the only genus of the natural order Rhizobokreece, one of whose species yields the Butter-Nuts of the London fruiterers' shops. One species is described by Aublet, under the name of Pekea butyrosa, as a large tree with a trunk 80 feet high, and 3 feet in dia meter. The berries are covered by a riud two or three lines thick, and consisting internally of a buttery yellowish substance, which melts between the fingers, and which is sometimes used in cooking instead of animal butter. Under the rind lies a stone covered all over with slender stings, which easily separate, and become very trou blesome to those who open the stones ; within is a kidney-shaped kernel covered with a brownish membrane, and very good to eat ; it is commonly served at table. It is called Pekea by the blacks in the neighbourhood of Oyapoco in French Ouyana, where it is much cultivated. The species that furnishes the Butter-Nuts of the London markets is much like this, but is called Tata-youba by the natives of Ouyana, and differs in having no stings upon the surface of the stone of its fruit : this is the Pekea tuberodosa of Aublet ; the Caryo car tomentoaum of modern botanists.
Another species, the Caryocar nuciferum, bears what are called the Suwarrow, or more properly Saouari, Nuts of commerce. It has only three leaflets to each leaf, each with a toothed margin and a taper pointed extremity ; the flowers are very large, deep brown externally and rich crimson in the inside ; the fruit is in form like an egg, covered with a thick rough brown rind, beneath which is a soft greenish buttery substance. The nut has a stinging surface, and contains a very excellent kernel, from which may be extracted an oil like that from sweet almonds.