摘要：Quercus undata Trel. (Fagaceae, Quercus, Section Quercus) has a complex taxonomic and nomenclaturalhistory. Intensive sampling of oaks at the type locality of Q. undata Trel. in Durango, Mexico and evaluation ofherbarium specimens and plants in the field indicate that Q. undata represents variation in Quercus chihuahuensis Trel.in white oak communities where introgressive hybridization among Q. chihuahuensis, Q. grisea Liebm., and a thirdwhite oak, Q. arizonica Sarg. made species identification difficult. Endlich’s type specimen of Q. undata, as designatedby Trelease, was apparently destroyed in bombing raids on Berlin during World War II, and we propose herein aslectotype the Trelease illustration of the type. An epitype is also designated in support of the lectotype, given that somefeatures cannot be critically observed on the illustration. The long peduncles of the specimen illustrated by Treleaseindicate a close relation to Q. chihuahuensis.
关键词：Biología; Botánica; Taxonomía;Sierra Madre Occidental; Mexico; epitype; lectotype; introgressive hybridization
