East Africa harbours several shrubby, spiny Euphorbia species which are often difficult to tell apart.
The species shown here occurs in northern Kenya and adjacent areas in Uganda and Ethiopia in very open bushland (often on lava) at altitudes between 400 and 1500 m.
The plants are mainly branched from the base and are up to 1.5 m(sometimes 2 m) tall. They have branches with 4-8 (usually 5-6) angles, up to 4 cm thick but somewhat constricted every 10-30 cm, usually with darker markings around the teeth.
Pictures 1 and 3 were taken last September south of Mt. Kulal on the eastern side of Lake Turkana in Kenya. The other two are scans from slides made in 1990 west of the lake.