Annual or occasionally perennial, 12–30 cm tall, unbranched or branched from the base, usually succulent, drying black or brown, sparsely to densely hispid or pilose; stem terete or obtusely square. Leaves 4–10 x 1–3 mm, opposite or subopposite, lanceolate, scale-like, appressed, entire, usually shorter than internodes, with obscure veins. All bracts similar, 2.5–6 x 2–3 mm, lanceolate, longer or shorter than calyx. Flowers opposite or subopposite in simple spikes, spike shorter or longer than vegetative stem. Calyx 5-ribbed, 4–9 mm long; tube 3–6 mm long; lobes 5, unequal or subequal, linear, deltate or lanceolate, 1–3 mm long, shorter than tube. Corolla creamy-white, blue, pink or purple; tube 8–14 mm long, bent and expanded distally above calyx, pubescent with very few sometimes glandular hairs; lobes of lower lip 2–6 x 1.3–3 mm, obovate, spreading; upper lip 1–2 x 2–2.5 mm, indistinctly 2-lobed or emarginate.