Annuals, 5-40 cm; taproots slender. Stems usually 1, sometimes 2-6+, erect to ascending, slender, usually much branched from base, divaricately so, densely hispiduloso-glandular, viscid. Leaves basal and cauline; proximal petiolate, distal sessile, often clasping; blades oblanceolate to oblong, reduced distally, 10-50(-70) × 1-25 mm, herbaceous, margins coarsely dentate or pinnatifid, apices of teeth or lobes spiny-tipped, faces glandular-hispidulous. Heads borne singly (terminal),often in loose, leafy, corymbiform arrays. Involucres hemispheric, 4-5 × 6-8 mm (fresh). Phyllaries in 2-3 series, appressed to reflexed distally, lanceolate, 1-5 mm, bases whitish, margins ± entire, apices green or sometimes purplish, acute, faces hispiduloso-glandular. Ray florets 20-35+; laminae lavender to whitish, 5-7 mm, coiling after flowering. Disc florets 25-40+; corollas yellow, 3-6 mm. Cypselae oblanceolate, 1.4-2 mm, smooth, faces sparsely sericeous; pappi: ray 0; disc white, terete, 1.5-3 mm. 2n = 10. Flowering Mar-Nov. Dry, open sandy flats, edges of playas, gravelly washes, riverbanks; 70-1000 m; Ariz., Calif., Nev.; Mexico (Sonora). Arida arizonica is a widespread and variable species recognized by its annual habit, deeply lobed or pinnatifid leaves, dense glandularity, relatively small heads with lavender to whitish ray florets, and absence of pappi on the ray florets.

Plant: Annual; stems branched from base, 5-30 cm, glandular with nonglandular hairs interspersed Leaves: generally sessile, simple, alternate, 1-30 mm, 1-10 mm wide, oblong, toothed to pinnately lobed; lobes and teeth bristle-tipped; upper leaves reduced, appressed INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate, solitary or in cymes; involucre 3-6 mm, 5-10 mm wide, hemispheric; phyllaries in 2-3 series, oblong to oblanceolate, glandular Flowers: Ray flowers 25-35, < or = 7 mm, white to lavender; Disk flowers 28-45, 2.5-3 mm; corollas yellow; style tips triangular to linear, acute Fruit: achenes, 1.4-1.9 mm, hairy; ray pappus 0 or obscure; disk pappus of many bristles, 2-3 mm, white Misc: Riverbanks, sandy, alkaline flats, roadsides; 30-300 m.; Mar-Jun References: J.C. Hickman, ed. The Jepson Manual.USDA website. (plants.usda.gov) ASU specimens.