Densely pubescent, annual herb with several spreading branches from the base, the latter usually gridled by the old disc-like fruit. Leaves petiolate, oblong-ovate, 5-20 x 3-15 mm, irregularly sinuate to pinnatifid, obtuse. Flowers small, inconspicuous, solitary axillary or paired. Epicalyx present as 5 lobes alternating with and equal to the calyx-lobes. Petals 5, greenish to pinkish. Fruit disc-like, woody with sharp spinous projection on the upper surface and a flat bottom, often 5-angled, 10-20 mm across.