Justicia insularis ?
Observed growing among roadside weeds below Iten on the Elgeyo Escarpment, Kenya, Africa. July 2014.
LEAVES: Lance-shaped leaves are opposite on the stems. Veins prominent on underside. Margins are smooth.
HERBACEOUS: Herbaceous growth from a base that might be woody and reaching mostly 1 meter tall with a number
of clustered stems. 
FLOWERS: Two lipped, lavender flowers are in clusters in the leaf axils. In the throat are lines of darker purple and white serving as a nectar guide for bees.
RANGE: One of several species of Justicia found in highland
areas of Kenya and Rift Valley.This is one of the more common species.
FRUIT: Two-valved, capsules.
UNARMED.