Date Published or Written
We report here on the flora of the Sierra de los Ajos, Sonora, Mexico, based on collections made in 1992 and 1993. The known flora of this Sky Island range contains 376 species of vascular plants in 93 families. Based on our collections and the results of floristic studies of other Sky Island ranges, we anticipate that the total flora of the Sierra de los Ajos contains over 1000 species. We have documented the only known occurrences in Mexico of two species that are candidates for
listing as threatened or endangered species in the United States, various new distribution records for Mexico and Sonora, and large range extensions of a number of other plants. This work contributes to a projected flora of the Sky Island region.