The new combination Hydrolea spinosa var. cervantesii (Brand) L. J. Davenport & A. Pool is proposed for the illegitimate name Hydrolea spinosa var. maior (Brand) L. J. Davenport. In the process of editing the Hydrophyllaceae for the Flora de Nicaragua, the junior author discovered a range extension into Nicaragua (Estelf, Moreno 25138, MO) of Hydrolea spinosa var. maior (Brand) L. J. Davenport. This taxon-native to stream and pond margins, like other members of the genus-was previously reported only from the Pacific slope of Mexico and Guatemala. Along with the range extension, an error in the original publication of its name was noted. In Davenport's (1988) monograph of Hydrolea, he proposed the new combination Hydrolea spinosa L. var. maior (Brand) L. J. Davenport based on Hydrolea cervantesii Brand var. maior Brand. Hydrolea cervantesii was cited as a synonym of this new combination; i.e., the type of H. cervantesii was included within the circumscription of the varietal taxon. When Brand (1913) proposed his variety maior, he automatically established the autonym Hydrolea cervantesii var. cervantesii. Following Article 11.6 of the International Code of Botanical Nomenclature (Greuter et al., 1994), the autonym has priority over names of the same date that established it. Therefore, H. cervantesii var. cervantesii has priority over H. cervantesii var. maior at varietal rank. Since the types of both cervantesii and maior are included within a single varietal circumscription, a new trinomial combination in Hydrolea spinosa is needed and so is proposed below. Hydrolea spinosa L. var. cervantesii (Brand) L. J. Davenport & A. Pool, comb. nov. Basionym: Hydrolea cervantesii Brand var. cervantesii, in Engler, Pflanzenr. IV. 251 (Heft 59): 184. 1913. TYPE: Mexico. Cervantes s.n. (not seen; possibly with other Cervantes material at BR, B, MA, or MEXU [Lanjouw & Stafleu, 1954]). Hydrolea cervantesii var. maior Brand, in Engler, Pflanzenr. IV. 251 (Heft 59): 184. 1913. Syn. nov. Hydrolea spinosa var. maior (Brand) L. J. Davenport, Rhodora 90: 187. 1988. TYPE: Mexico. MichoacAn or Guerrero: El Ocote, 12 Nov. 1898, Langlassd 619 (holotype, G not seen; isotypes, GH, US). Acknowledgments. We thank W. D. Stevens for his advice and encouragement.