Erect undershrub, glabrous, much branched, often tinged with purple; leaves broadly ovate-lanceolate, obliquely cuneate at base, entire or deeply toothed, pubescent; flowers axillary, solitary; peduncles minutely pubescent; calyx tubular, pubescent outside, lobes 5, lanceolate, acuminate; corolla purplish outside, white inside, lobes-5, 10-plaited, tips triangular-acute; stamens 5, fillamets long, attached to corolla tube up to half of their length; anthers linear, included dehiscing longitudinally; ovary 2-4 celled, many ovuled, style long, stout, stigma slightly 2-lobed; capsule globose, spinous with short tubercles, brown when ripe, subdehiscent; spines short, stout, blunt, sometimes forked; seeds many, subreniform, brown.