Wislizenus' Senna or Shrubby Senna (Senna wislizeni) has been added to my Wildflowers of Tucson, Arizona website. These shrubs are blooming in the lower Tucson foothills and can usually be found growing from 3000 to 4000 feet (914 to 1219 m) in elevation. The golden yellow flowers on this native, desert shrub contrast nicely with its dark foliage and bark, making it an attractive choice for a desert garden.
Native sennas, such as this one, serve as food plants for Cloudless Sulphur (Phoebis sennae) larvae, and when I was photographing these plants, I saw a Cloudless Sulphur butterfly fluttering about the flowers and briefly landing on them. I also observed a rather large Cloudless Sulphur caterpillar resting in the shade under the flowers, and it can be seen on the right in the photo above.