Good morning David!
I id some digging around here this morning:
According to this Kew entry cactiformis is a synonym for quadrangularis.
http://apps.kew.org/efloras/na...
I should point out that those tiny round thingies are only the buds. I was watching it very carefully that time and then took pictures of the ridiculously tiny open blooms.
I would think I didn't have a pollinator around, I never got berries/fruits as the spent flowers simply dropped off.
