Plant: Annual 1-12 dm, aromatic; branches generally stiff, bristly Leaves: generally cauline, alternate; lower 5-15 cm, linear-lanceolate, deeply 2 X divided; upper linear, spine-tipped, glabrous to scabrous, margin stiff-ciliate, generally with axillary leaf clusters INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads ± clustered; involucre 3-6 mm, generally overtopped by upper leaves; phyllaries keeled, spine-tipped, scabrous; chaff scales scattered, generally spine-tipped Flowers: Ray flowers many; ligule 3-5 mm, 2-lobed, yellow; Disk flowers many, generally staminate; corollas and anthers yellow; anther tips ovate; style branches long, tips bristly Fruit: achenes, ± 2 mm, beaked; ray achenes ± 3-angled; pappus 0; disk achenes cylindric or obconic, disk pappus 0 Misc: Grassland, depressions, marshes; < 500 m.