Small, perennial herb, up to 25 cm tall. Branches slender, rigid, often leafless later in summer. Leaves shortly-petiolate to sessile, small, oblong to linear, up to 25 x 5 mm, crenate, often revolute-margined. Verticillasters (whorle-like dichasial cyme) 2-6-flowered, distant and arranged in terminal racemose inflorescences; floral leaves and bracteoles minute. Flowers very small, pedicellate. Calyx 3-4 mm in flower, up to 7 mm in fruit; upper lip with 3 closely connivent minute teeth, becoming upwardly concave in fruit; lower lip with 2 acuminate-subulate teeth. Corolla whitish to violet-blue, small, rarely exceeding 5 mm; upper lip straight or reflexed, shorter than the lower lip. Nutlets black, oblong, 2 x 1.25 mm.