S. stomandrus is a vigorous upright/trailing species, one of the parents, with S. saxorum, of the widely grown S. ‘Concord Blue’. While rarely seen it remains in cultivation and is commercially available.
Note the dark markings on the lower lobe near the throat, characteristic of the species and passed on in somewhat different form to S. ‘Concord Blue’.
In the most recent botanical studies on Streptocarpus, this species is allied to S. saxorum, within subg. Streptocarpella sect. Carnosifolii.
Another photo can be seen here.