Abstract: Erigeron, Bromus, Muhlenbergia, and Oenothera were the most represented genera. Nonnative taxa accounted for seven percent of the total flora. Stachys albens was vouchered as a new state record for Arizona. New county records include Graptopetalum rusbyi (Coconino), Pseudognaphalium pringlei (Coconino), Phaseolus pedicellatus var. grayanus (Coconino), and Quercus rugosa (Coconino and Yavapai).
This study also quantified and contrasted native species diversity in canyon versus non-canyon floras across the Southwest. Analyses based on eighteen floras indicate that those centered about a major canyon feature show greater diversity than non-canyon floras. Regression models revealed that presence of a canyon was a better predictor of similarity between floras than was the distance between them. This study documents the remarkable diversity found within canyon systems and the critical, yet varied, habitat they provide in the southwestern U.S.
