I realized after I posted about P. "Burgundy" that I should have included a photo of P. sidoides in the post. Here it is, blooming in my school garden. Note how dark the flowers are, much more so than "Burgundy" is. "Burgundy" also produces more elongated foliage bearing stems than does true P. sidoides.
I believe that P. sidoides has been used as a respiratory medicine in traditional African medicine (and in Europe), and I would expect P. reniforme to have similar pharmaceutical properties. Unfortunately this poses a danger to these plants in the wild, as they are gathered as "muti" by traditional healers in their homeland. They could be easily cultivated in areas with appropriate climates so as to relieve pressure on wild populations.