XVI International Botanical Congess

The genus Stenocereus includes a group of eight species with brown areoles indigenous to Western Mexico. The color is due to the presence of glandular trichomes. Although the genus has been studied by several authors, relationships among species are not clearly understood. Her we test the monophyly of the species with glandular trichomes. Our parsimony analysis uses more than 30 characters and includes all the species with glandular trichomes and representative species which lack this gland. The results show that S. queretaroensis, S. chrysocarpus and S. montanus group in a clade strongly supported. Stenocereus queretaroensis is closely related to S. montanus and not to S. thurberi as previously suggested. The remaining species were grouped in a second clade characterized by an horizontal notch between areoles. Our results do not support the inclusion of S. fricii within the clade with glandular trichomes as hypothesized by other authors.