Sinningia sp. "Black Hill"

Sinningia sp. "Black Hill" combines the two features.  Its tubers are at or near the surface, but composed of numerous lobes.  Notice the satellite tubers on the roots.  This species is one of those with a perennial stem.  In most sinningia species, the plant dies back to the tuber in the winter, but this species, together with S. reitzii and S. mauroana, retains some or all of the stem for the next year.