Nearby a patch of intergrading Aquilegia pubescens and Aquilegia formosa; see my other photo for an image of clearly intergrade plants. I judged this individual to be pure pubescens, but it's possible it's a pubescens-like intergrade.
According to John Harris, Ph.D., Professor of Biology at Mills College, who led me to this flower, it probably is a hybrid between Aguilegia formosa (Photo ID 1073 3282 1658 0021) and Aquilegia pubescens (Photo ID 1073 3283 1658 0022). Both parent plants are only a few feet away.
moist soil of road cut seep in volcanic tuff, later destroyed by new highway construction. This barrel flowering species displays an exceptionally large and beautiful flower and should be well suited for temperate gardens