Common spikeweed

Centromadia maritima Greene; C. pungens subsp. maritima (Greene) B. G. Baldwin; C. pungens subsp. septentrionalis (D. D. Keck) B. G. Baldwin; Hemizonia pungens (Hooker & Arnott) Torrey & A. Gray subsp. maritima (Greene) D. D. Keck; H. pungens subsp. septentrionalis D. D. Keck; H. pungens var. septentrionalis (D. D. Keck) Cronquist

Leaves: margins sometimes ciliate, faces glabrous, scabrous, or hirsute, midribs sometimes bristly. Paleae often exserted, apices ± attenuate, spine-tipped. 2n = 18, 20.

Flowering Apr–Nov. Open, ± alkaline flats, depressions, waterway banks and beds, in grasslands, saltbush scrub, disturbed sites (e.g., fallow fields); 0–1200(–1800) m; Ariz., Calif., Idaho, Nev., N.Y., Oreg., Wash.; Mexico (Baja California).

Subspecies pungens is circumscribed broadly to include subsp. maritima and subsp. septentrionalis based on morphologic and molecular data (B. G. Baldwin, unpubl.). As treated here, Centromadia pungens subsp. pungens occurs widely in central and northern California, and it is putatively introduced in southwestern California and outside the state.