This native plant is a summer annual about 4-8" tall that branches occasionally. The stems are light green to reddish green, 4-angled, and hairless. The opposite leaves are up to 1½" long and ¾" across; they are oval-ovate in shape, light green to reddish green, hairless, and smooth along the margins or bluntly dentate. The upper surface of each leaf has 3-5 pale veins, while the base of each leaf is sessile or has a short petiole. Individual flowers are produced from the axils of the upper leaves (one flower per axil). Each flower is up to 1/3" long, consisting of a tubular calyx with 5 linear teeth and a tubular corolla that curves slightly downward. The calyx is light green to reddish green and hairless. The corolla is white, pale violet, or a combination of these two colors. The upper lip of the corolla has 2 small lobes that function as a protective hood, while the lower lip of the corolla has 3 lobes that are rounded and spreading. Inside the corolla, there are 2 fertile stamens, 2 sterile stamens, and a single style. The slender pedicel of each flower is up to 1" long; it is usually shorter than the leaf underneath the flower. The blooming period occurs during the summer and early fall and can last 2-3 months for a colony of plants. There is no noticeable floral scent. Each flower is replaced by a narrowly ovoid or spindle-shaped seed capsule containing several small seeds. Mature seed capsules are about as long as the teeth of the calyx or slightly longer. The root system consists of a branching taproot. This plant reproduces by reseeding itself and occasionally forms colonies.