Rafinesquia neomexicana. Jepson Manual notes that it often grows supported by branches of a shrub like this -- seems like a lifestyle sort of halfway between a freestanding plant & a vine. Not the best shot, but it does show that habit, and also the pale purple streaking sometimes present on the outside.
Rafinesquia, commonly known as Plumeseed, is a genus of flowering plants in the family Asteraceae which are native to the west of the United States and Mexico.
