Aloysia polystachya

These plants are subshrubs, shrubs, or trees growing 0.5 meters to 15 meters tall. Many are very aromatic. The stems may be four-angled and smooth when new, becoming more angular or rounded and often furrowed or striated with age. The leaves are evergreen or deciduous in the dry season. They are often oppositely arranged or whorled, but can be alternate or clustered. The blades are variable in shape, toothed or smooth-edged, and hairless to rough-haired on the upper surfaces. The undersides may have glandular hairs. The inflorescence is usually a raceme of widely spaced clusters of 3 to 6 flowers each. There are leaflike bracts under the flowers which can be showy in some species. The calyx of sepals has 2 or 4 lobes and is persistent, enclosing the fruit as it develops. The flower corolla is tubular with a wider mouth divided into four lobes, one of which may be cleft. The corolla can be white, purplish, blue, or pink. The narrow style is tipped with a bilobed stigma and there are 4 stamens. The fruit is a schizocarp.