Quercus tuitensis (Fagaceae, Quercus sect. Lobatae), a new deciduous oak from western Jalisco, Mexico. Brittonia 55: 42–48. 2003.—Quercus tuitensis, a deciduous red oak known only from the Sierra El Tuito on the Pacific slopes of western Jalisco, Mexico, is described, illustrated, and compared to Q. praineana Trel. In addition, Q. aequivenulosa and Q. coffeaecolor are reaffirmed as synonyms of Q. praineana.