A greyish-villous perennial with decumbent or ascending stems, branched from the base; leaves are oblong-linear to linear, usually entire or 1-3-dentate at tip; verticillasters are 2-flowered, forming a raceme-like inflorescence; calyx is tubular and villous and calyx-teeth are triangular and acute; corolla is yellow or purple; fruit is a pitted nutlet.