Speaking of that weird "U. microcalyx" plant. If it didn't seem so darn unlikely, I would swear that it was a cross between U. livida and U. sandersonii. Look at the top corolla lobe: it looks like what I would expect a cross between the two to look like - some flowers even have a notch in the centre o fht top lobe, but the colouring alone reminds me of U. sandersonii. The bottom corolla lobe also has similar markings and shape to U. sandersonii, just much larger.
The two plants are quite closely related, and I seem to remember one of the first people I saw with it on their growlist claimed that it had just "appeared" in a pot.
By the way, this whole discussion about how many varieties is an excellent argument for formally registering cultivars.
I definitely see how you see U. sandersonii in this not_microcalyx. I have suggested the same possibility. I don't get the "feel" that this is just a U. livida variation.
Hmmm, the variability could also argue FOR formal registration. How else to distinguish one variation from the other when trading/buying/selling? I wonder how many different clones are actually being cultivated? A lot of times this material stems from small initial collections widely distributed over time.
I have a U. Livida too. I don't know what variety...I'm assuming it's just a typical. It hasn't flowered yet...and it...may...not *tear* It's hanging in there though. Darn you algae!