Opuntia rufida
A plant of the Big Bend region, much like Opuntia engelmannii but with spineless pads. At least, the large spines are absent--glochids are still present in abundance.
Flowers, on limestone bluffs near Tornillo Creek at Big Bend, 15 Apr 2007.
Plant habit (left), with Opuntia X spinosibacca (right) overlooking Tornillo Creek.