We stopped on the way back from a visit to Mom at the retirement ranch and I took this photo of a flowering buckhorn cholla. This one has many blooms on it. The buckhorn cholla in and around our yard have a few open flowers, but not as many as this one. Click on the image to enlarge.
Snippet from eNature.com:
Opuntia acanthocarpa – buckhorn cholla
The main trunk of this tree-like cactus is short and erect; branching open and low to ground. Branches are cylindrical; the joints light green.
Habit: native perennial shrub; succulent stems, in segments 4-20 in (10-50 cm) tall by 0.75-1.25 in (2-3 cm) diameter; new growth is gray-green to purple-green; old growth has rough, scaly, brownish black bark.
Flower: delicate, lemon yellow to copper to red to pink, 2-3 in (5-7.5 cm) wide.