This is the most taxonomically frustrating taxon in the family. It is native from southern Lake Turkana to Mandera District in Kenya and throughout southeastern Ethiopia. It doesn't seem to extend far into Somalia. Subspecies rivae is recognized as having creamy petals with brownish tips and short fruits. Subspecies longisiliqua has yellow flowers and very long fruits. I am currently testing the status of these entities but much collecting still remains to be done in southeastern Ethiopia and northeastern Kenya to resolve the issue.
The individuals I have seen have all been large shrubs to 3 meters tall with greatly swollen roots. Some herbarium specimens, particularly of ssp. longisiliqua, report an arborescent habit to over 6 meters tall.
Moringa rivae is very similar to M. arborea and M. borziana.
Remarkably, Samburu, Turkana, and Rendille people of Kenya use the same common name "lorsanjo" for both the massive M. stenopetala and the much smaller M. rivae. Likewise, Somalis of northeastern Kenya call all five species in the area "wamo".
I reached the locality pictured below by small airplane. Bad rains had washed out many roads, and what would have been a grueling two-week drive was an hour-long hop in the plane. When we landed in this very remote area, we were surprised to be greeted by a young Rendille who was herding his family’s goats. His English was perfect! We spoke with him at length about life in the area. He was on Christmas vacation from his school in Marsabit and had managed to catch up to his pastoralist family who was following the rains to graze their livestock. We have stayed in touch with him and followed his progress as he and his family struggle to find enough money to send him through school. If you've never corresponded with a nomad, now is your chance: he greatly appreciates letters of encouragement. His address is: Jonah Rupaile Samanah, Box 292, Marsabit KENYA.
1. Habit of plant in dense scrub; 2. M. rivae fruits and leaves; 3. Seed; 4. Locality Mt Baio, Kenya