Free amino acids in seeds of 22 species of Crotalaria (Leguminosae) which grow in South America, Asia and Australasia have been identified. The position of these species in recent classifications of the genus is assessed on the basis of the distribution offree amino acids and alkaloids in their seeds as well as on the basis of morphological characters. The alkaloid 1‐methylenepyrroiizidine is shown to occur in seeds of 4 species in which it has not been identified previously. Copyright © 1979, Wiley Blackwell. All rights reserved