Arizona sneezeweed

Annuals, 30–70 cm. Stems usually 1, sparingly branched distally, weakly winged, glabrous or sparsely hairy. Leaves glabrous or sparsely hairy; blades all lance-linear, entire or coarsely toothed. Heads 1–15(–25) per plant, in paniculiform arrays. Peduncles 4–13 cm, glabrous or sparsely to moderately hairy. Involucres globoid to ovoid, 11–16 × 14–20 mm. Phyllaries sparsely to densely hairy. Ray florets 12–18, pistillate, fertile; corollas usually yellow, sometimes yellow with purple streaks, 10–20 × 5–13 mm. Disc florets 300–500(–700+); corollas yellow proximally, yellow to purple to dark blue-purple distally, 3.2–3.6 mm, lobes 5. Cypselae 2–2.9 mm, moderately hairy; pappi of 6–7 entire, aristate scales 1.5–2 mm. 2n = 30.

Flowering Jul–Sep. Pine forests, edges of wet places such as bogs, ponds, lakes, ditches; 1800–2400 m; Ariz.