Due to molecular evidence, Seemannia was re-established as a distinct genus relatively recently. It had been lumped into a more broadly-defined Gloxinia for several decades prior to that, so it may still be encountered in gardens or garden catalogues as Gloxinia sylvatica.
Of the four species in the genus, Seemannia sylvatica is the only one in widespread cultivation. John Boggan, of Washington, DC, is a plant breeder who has made attempts to change that. Please see his discussion of Seemannia: a gesneriad with commercial potential from his DC Tropics weblog. In the future, members of the easily-grown Seemannia will perhaps be broadly available, at least as bedding plants.
It’s a challenge to discern whether Bolivian sunset is a common name for this species or whether it is a bona fide cultivar that is often misapplied. Still, the term is useful to reveal the species’ South American origins. Seemannia sylvatica is native to Peru, Bolivia, northern Argentina, Paraguay, and southern Brazil.
For additional reading, check out a florid description of Seemannia sylvatica via The Plant Provocateur’s weblog: Smokin’ Hot Electric Lava Drops. Or, to see more images, check out the Seemannia photo gallery via Gesneriads.ca.