Much branched, erect, hispid, annual herb; roots conical or fusiform; leaves pinnately decompound, ultimate segments linear, acute, florals masses small, numerous, many rayed, flattened; umbels white, involucral bracts foliaceous, divided pinnately into linear segments, bracteoles linear or 3 parted; pedicels short; calyx teeth minute, mouth truncate; petals-5, often inflexed, white, obovate, free, emarginate, unequal, valvate or imbricate; stamens 5, epigynous; ovary 2-locular, crowned with a large epigynous disk; 1-ovule, pendulous in each locule, styles 2; fruit of 2 indehiscent carpels, pendulous from summit of the undivided carpophore, each prominantly 5-ridged; fruits oblong, bristly, ribbed.