Two species of Trichostema L. (Ajugoideae, Lamiaceae) from western states need nomenclatural clarification. Trichostema simulatum Jeps. occurs throughout northern California and southern Oregon. It was published by Willis Linn Jepson in his 1925 flora of California citing the type collection as “Klamathon, Copeland 3534, Type”. This is a conflation of the collector's name and the specimen number of the exsiccata West American Plants, in which the type specimen was distributed by C. F. Baker in 1903. Furthermore, an herbarium name, “Trichostema laetum Greene,” appears on most T. simulatum type material. This designation was never published and is a nomen nudum. Trichostema austromontanum F.H.Lewis occurs throughout the mountain ranges of southern California and Baja California. Originally published with two subspecies by Harlan Lewis in 1945, the three taxa have since been determined to be invalidly published because Lewis did not provide a species description, only subspecies descriptions. Herein, we provide a clarification on the type specimens of T. simulatum Jeps. as well as a valid publication of the species name T. austromontanum.