Streptocarpus candidus

Photo by Dirk Bellstedt
Grown at Kirstenbosch National Botanic Gardens, South Africa

Another image of a show plant illustrates the very floriferous nature of this species, as does this photo of a clone distributed by Dibley's Nursery in Wales.  The clone shown here also has a slight lavender caste to the outside of the tube, and has less distinctive face markings than the Dibley clone.  

The blue flowers to the left are S. caeruleus.