Sinningia sellovii

Photo by Ron Myhr
Grown at Smithsonian Institution Greenhouses

The flowering inflorescence of this plant arched above the foliage, with the tip ending up facing down. 

There are a number of photos of S. sellovii on the site:

S. sellovii yellowish form, available light and flash
S. sellovii shown at AGGS Convention 2004, flowers and whole plant/tuber
S. sellovii photos at the Smithsonian, flowers and stems
S. sellovii flowers, Toronto show 2004