Annual, prostrate or procumbent, ascending, thistle like herb with white tomentum; stem much branched from the base, spreading, rigid, clothed with white tomentose; leaves sessile, alternate, oblong, pinnatifid, lobes triangular, spinescent; spines 3-4 cm long, pale scabrous above, white, arachnoid beneath; heads compound, globose, forming a spherical ball, blue or white; florets bisexual, white, sessile or shortly stipitate, surrounded by white pappus-like bristles; involucre oblong, bracts 6-8, oblanceolate, glabrous, rigid, pungent, multiseriate, spinescent; outer shorter, inner spathulate, innermost linear-lanceolate, sometimes all connate into a tube with single sharp spine on outer side; receptacle minute; corolla white, tubular, tail short, entire or fimbriate, 5-lobed; filaments glabrous, anther-bases sagitate, auricles connate; style arms with a thick basal ring, spreading; achenes elongate, densely villous, pappus with a crown of many, short, free or connate bristly hairs.