Photo by John
Growing in nature in Ecuador
This photo nicely illustrates the way the small flowers cluster in the leaf axils, as well as the interesting and robust reddish stems (a variable feature) and pronounced anisophylly -- the leaves are produced in pairs, but one of the pair becomes so reduced in size (and often eventually drops off) that the leaves appear to be alternate. Other photos illustrate the flowers and red-spotted leaves (here and here) along with the much more prominent lilac-colored berries (here and here).
The individual flowers are quite hairy and produce lots of pollen, as can be seen here.