Three recent phylogenetic studies have used DNA sequence data to examine evolutionary relationships in Amsinckiinae (Boraginaceae). In each of these studies, the genus Plagiobothrys Fisch. & C. A. Mey. has been recovered as non-monophyletic. So that only monophyletic groups are recognized, two new genus names are provided here: Amsinckiopsis (I. M. Johnst.) Guilliams, Hasenstab & B. G. Baldwin and Simpsonanthus Guilliams, Hasenstab & B. G. Baldwin. The new combination P. collinus (Phil.) I. M. Johnst. var. pringlei (Greene) Guilliams & B. G. Baldwin is given for plants from Arizona that were found to be phylogenetically nested within P. collinus. The genus name Sonnea Greene is lectotypified.