 The genus name is based on the Greek 'amphi-' (=double or of two kinds) and 'stemon' (=stamen) referring to the dimorphic stamen position characteristic for this genus.Amphistemon are erect perennial herbs or subshrubs with the unique feature in the "Hedyotis"-"Oldenlandia" group of having stamens inserted at two distinct levels in the corolla tube, the lower stamens with filaments and anthers shorter than those of the upper stamens.It is endemic to southwestern and western Madagascar and is found in dry spiny forest-thicket and coastal bushland.