Numerous wheat varieties have been yearly introduced in the State of São Paulo by the Division of Genetics of the Instituto Agronomico of Campinas. Among these, twenty-seven varieties have shown, after 3 years' observation, to be the most adapted to the soil and climate conditions of the State of São Paulo. The present paper deals with the botanical study of these 27 varieties in order to determine whether they are distinct among themselves, or whether two or more of these varieties presenting different introduction dates, names, and origin, actually belong to the same variety. In developing this project the authors based their observations upon the scheme of characteristics previously utilized by Horovitz and Clark & Bayles. An artificial key for classification is also proposed, in which the varieties are arranged according to the criteria already employed by Percival. It was verified that the 27 commercial varieties herein described belong to 10 of the known botanical varieties of Triticum sestivum L.