Spending the winter in the sunroom seemed to agree with my 'Irene Nuss' Begonia. I've had to stake it to keep the heavy blooms from bending the canes over.
doesn't look the same as the other photos, but the folks at the Huntington swear this is it.
'Irene Nuss' with b. theimei to the right front and tuberous begonia 'Illumination' in the back.
Bloomed all winter.
'Irene Nuss' in front of the pond
The Huntington Botanical Gardens