This perennial plant is 1-3' tall, branching occasionally to frequently. The light green stems are glabrous and bluntly 4-angled, but they are not conspicuously winged. The opposite leaves are up to 4" long and 1" across; they are light to medium green, lanceolate or elliptic-oblanceolate in shape, glabrous, and serrated to sparingly serrated along their margins. The leaves are sessile or they clasp the stems; petioles are absent. Leaf bases are round to slightly cordate, while their tips are slender and pointed. Individual flowers develop from the leaf axils of the middle to upper stems. These flowers are about 1" long, and they have two-lipped corollas that are usually pale blue-violet (less often pink or white).