Climacium dendroides (Hedw.) F. Weber & D. Mohr is reported new to Mexico and in the first known locality in the tropics, at the elevation of 3,000 m, on the ancient shield volcano of Cofre de Perote. Variation in branching of the costa is assessed in this plant and in material of C. dendroides worldwide. Additional taxa of interest from this locality on Cofre de Perote include Aulacomnium palustre and Polytrichum commune (both new to the state of Veracruz).