Erect or ascending, perennial herb; stem with purple tinge on nodes; leaves opposite, subsessile, elliptic to oblanceolate or even rhomboid, entire, acute or acuminate at apex, long-attenuate below, often tinged with purple; flowers in axillary, white, ovoid to globose, sessile heads; perianth segments-5, lanceolate acute, mucronate with the excurrent midrib, the outer three prominently 3-nerved below, with white hairs outside; inner tepals shorter, 1-2 nerved; stamen 2-5, few fertile, anthers 1-celled, filaments distinctly connate below, alternating with large or small; pseudostaminodes as long as the filaments, laciniate at the apex; ovary 1-celled, ovule solitary, pendulous, style short, stigma capitate; urticles indehiscent, enclosed within persistent tepals, thin waled or corky; seeds lenticular.