Bushy, glabrous shrub or undershrub; stem angular, striate, much branched, shining; leaves opposite or whorled, upper reduce to scales; normal leaves very small, ovate to linear, lanceolate; flowers in lax, axillary and terminal long penduncled, dichotomously branched, many flowered cymes; pedicels slender, often pendent; bracts minute; calyx campanulate, deeply divided near the tip into 5, lanceolate, acute, glabrous, teeth; corolla scarlet, tubular, glabrous, lobes-5, subequal, obtuse; stamens-4, included; ovary 2-celled, glabrous, 2-4 ovuled, style filiform, stigma 2-lobed; capsules septicidally dehiscent, subglobse, glabrous; seeds ovoid, many, minute, smooth, black.