The presence of alkaloids in leaves of nine species of pines was indicated by qualitative tests. The possible relationship of these observations to Mirov's biochemical classification of pines is discussed. From leaves of P. sabiniana Dougl. two alkaloids were isolated: (+)-α-pipecoline and a new organic base, C9H17N, to which the name pinidine has been given. © 1955, American Chemical Society. All rights reserved.