Interesting things, flowering cacti — they give a photographer such a list of contrasts to work with. Bright vs. muted colors.
Spiky vs. soft shapes.
Angular vs. rounded shapes.
These are all shots of a “Nipple cactus” (Coryphantha sulcata, a.k.a. Pineapple cactus), seen at the Lady Bird Johnson Wildflower Center in Austin, Texas. At least, that’s how it was labeled — but all the online information on this species shows it to be both smaller and bearing yellow flowers. Not sure what’s going on there…