There seems to be some variation from the Durban form: darn that yellow spot in the center!!! Here is a form from South Africa that I cultivate:
Yours seems to be intermediate between this and the "so called "U. microcalyx" that is driving collectors bonkers all over the world:
and just for reference, here is U. arenaria:
and the "Durban" form:
and finally, the "typical" U. livida:
By comparison, your flower most resembles the "microcalyx" in my opinion. I remain convinced that the U. microcalyx we have been seeing is a form of U. livida, possibly a result of a natural or manmade hybrid between U. livida and something else: possibly U. sandersonii, but this is mere speculation since I do not yet have a copy of Taylor.
Look at the skirt of U. sandersonii "blue flower":
All these plants are obviously closely related! Both U. sandersonii and U. lidida have a yellow splotch. If you consider the leaf forms of U. sandersonii, U. livida "Durban" and U. livida "South Africa" all have a very different look from Typical U. arenaria or typical U. livida, the leaves are broader. The kicker is that the U. "Sp. 2" which I think most resembles the "microcalyx" in flower form also has these shaped leaves, and I would have expected that they would look more like the typical U. livida or U. "microcalyx" (as below)!!!
Both the U. "microcalyx" , U. arenaria and the typical U. livida have similar shaped "club like" leaves.
So you know as much as I do about it all now. Anyone care to venture an opinion?