Carya. Hicoria. Hickory.—Several species of the genus Carya Nuttall (Hicoria, Eaf.) grow in the United States of which Carya illinoensis (Wang.) K. Koch bears the pecan nut, and grows in the Middle and Southwestern States; C. ovata (Mill.) K. Koch, a large and handsome tree known as shell-bark or shag-bark hickory, is the chief source of the hickory nuts of the market. There are six other common species of carya which are indigenous to the United States and Canada, and all yield edible fruits. The leaves of most if not all of these trees are somewhat aromatic and astringent, and the bark astringent and bitter. In the bark of H. alba F. R. Smith found a crystalline principle, carryin, which he believed to be quercetrin.