PLANT: Suffrutescent perennial to 3 dm tall, branching at the base; stems erect, glabrous to short pubescent. LEAVES: lobes (4-)5-9, linear to oblong, spinulose, 10-20 mm long, short pubescent. INFLORESCENCE: compact, the flowers 2-5 in terminal, bracteate clusters. FLOWERS: subsessile; calyx glabrous to pubescent, narrowly campanulate, 7-10 mm long, the lobes longer than the tube, the membranes mostly herbaceous, the hyaline part narrow, often obscure; corolla diurnal, salverform, 8-15 mm long, the tube and lobes white, the throat yellow; stamens inserted on the throat; style slightly exserted. 2n=18. NOTES: 3 subspp.; w N. Amer. Reports of Linanthus nuttallii subsp. floribundus (Gray) Munz [Linanthus floribundus (A. Gray) Milliken] from AZ are incorrect. REFERENCES: Dieter H. Wilken and J. Mark Porter, 2005, Vascular Plants of Arizona: Polemoniaceae. CANOTIA 1: 1-37.