Herbs, with milky, narcotic juice. Leaves alternate. Flowers large, with caducous calyx. Ovary one-celled, with parietal placentae. The genus Papaver, a description of which is given under Opium, is typical of the order. See also illustrations below.

A Manual of Organic Materia Medica and Pharmacognosy, 1917, was written by Lucius E. Sayre, B.S. Ph. M.