CAUCASIAN WALNUT. WINGED WALNUT.--The winged fruit of _Pterocarya fraxinifolia_, also known as _P. Caucasica_ of nurserymen's catalogues. It belongs to the walnut family (_Juglandaceæ_), and is a tree growing thirty to forty feet high, somewhat resembling the common ash (_Fraxinus_). It is a pretty, hardy, ornamental tree, thriving only in moist soils. Seeds on winged nuts produced in long, drooping racemes, but of no special value. Introduced into England from Caucasus in 1800, and now plentiful here in nurseries. CHESTNUT.--See Chapter V; also Horse-chestnut, and Moreton Bay, Tahiti and Water chestnuts. CHOCOLATE NUT OR BEAN.--The seeds of a small tropical tree, _Theobroma Cacao_, of the chocolate nut family (_Sterculiaceæ_). Indigenous to tropical America, but now cultivated more or less extensively in all hot climates. The tree grows from fifteen to twenty feet high, with long, pointed, smooth leaves. The flowers are small, yellow, and produced from the old wood of both stems and branches, succeeded by a pod-like fruit six to ten or more inches long, containing fifty to a hundred seeds, resembling beans more than they do nuts. When the fruit is ripe it is gathered, at which time the seeds are covered with a gum-like substance, and to remove this they are subjected to a slight fermentation, after which they are dried in the sun, this giving them their usual brown color. Chocolate nut trees are extensively cultivated in Brazil, New Grenada, Trinidad, and, in fact, throughout tropical America, and their cultivation is, upon the whole, very profitable, as the demand is almost unlimited. CLEARING NUT.--This is an East India name for the seeds of _Strychnos potatorum_, a plant belonging to the well-known nux vomica family (_Loganiaceæ_). It is a small tree, native of India, the wood of which is used for various purposes. The fruit is about the size of a cherry, and contains one seed; this is dried, and used for clearing muddy water, this being effected by rubbing one of the little nuts around the sides of the vessel that is to be filled, after which the water is poured in, and then, through some unknown agency, all the foreign matter settles, leaving the liquid perfectly pure, clear and wholesome.