We encountered this species in Bolivia at roadside in secondary, disturbed habitat bordering cultivated fields in an area that was very arid and hot. Dead cayman nearby added to the ambiance.
Suffrutescent herb to 1 m, extremely abundant, corollas mostly purple but some plants producing flowers nearly white in color; plants formerly ascribed to Ruellia coerulea have be synonymized with Ruellia simplex, but this is the wild type and it is SO very different from Ruellia simplex.
Wild collected, Bolivia, Tripp #6020 w/ Luján, and Clark (COLO); Photos by Manuel Luján; Blog post by Dina Clark