Senna armata (Fabaceae), or desert senna, in bloom in the Mojave where Godwin Road meets Amboy Road. In early to mid-April, 2020, it was blooming at elevations between approx. 900' and 1650' as I headed north into the Mojave Preserve from Twentynine Palms.
Senna armata is a good native choice for raising Phoebis sennae marcellina in the garden. It may also be used by Phoebis agarithe, Abaeis mexicana, and A. nicippe.