Another tropical flower today, this time courtesy of zimbart@Flickr, aka Bart Wursten (original image 1 | original image 2 | via the UBC Botany Photo of the Day Flickr Pool). I believe this is the first time a photograph taken in the Democratic Republic of Congo has been used on Botany Photo of the Day. In addition to these photographs of the flowers, Bart has uploaded photographs of Rothmannia octomera's habit, calyx and fruit.
As a member of the Rubiaceae, Rothmannia octomera is related to such economically important plants as Coffea spp. (responsible for coffee), Cinchona spp. (source of quinine), as well as a number of ornamentals. This latter category includes some other species of Rothmannia, such as Rothmannia capensis. One of the few human uses of Rothmannia octomera that I can find is its use as a dye--the extracted fruit juice is used as a black ink for darkening tattoos or drawing designs on skin.
The species is noted as being common in terra firme, or unflooded, rainforests as well as the edges of seasonally-flooded forest in central Africa. A short description of this 3m tall shrub, as well as additional photographs, is available via the Royal Botanic Gardens Edinburgh's An Introduction to the Trees from the North of the Republic of Congo: Rothmannia octomera.