Ulmus crassifolia Nutt. Ulmus crassifolia Nutt. in Trans. Amer. Philos. Soc., n. s., 5 (6[2]): 169. 1837 sec. Villaseñor & al. 2010=Ulmus monterreyensis C.H. Mull. in Amer. Midl. Naturalist 27: 483. 1942 syn. sec. Villaseñor & al. 2010