What Are Stipules?: 'The Nature and Origin of Stipules,' by A. A. Tyler, A. M. Presented to the Faculty of Pure Science of Columbia University in partial requirement for the degree of Doctor of Philosophy. Annals of the New York Academy of Sciences, Vol. X., New York, 1897, pp. 1-49, pl. i.-iii. Also separate: Contributions from the Department of Botany of Columbia University, No. 119.