Annual, 15-50 cm tall, branched. Stem glabrous. Leaves much divided; ultimate segments filiform. Involucre of 5-8 linear, sometimes pinnate, bracts. Rays 8-16, glabrous, unequal. Involucel of 5-8 linear, sometimes pinnate bract-lets. Pedicels twice as long as the fruit. Fruit ovoid, 2 mm long, muricate; ridges not prominent; stylopodium conical; styles c. mm long.