Blueweed, blue boneset

Eupatorium azureum A. P. de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 168. 1836

Leaf blades mostly 20–50+ × 15–40+ mm. Involucres 6–8 mm. Corollas ca. 6 mm. Cypselae ca. 2.5 mm; pappi ca. 4 mm. 2n = 20.

Flowering Feb–Jun(–Jul). Shrublands, often with acacias, palm groves, clay or clay-loam soils; 0–10 m; Tex.; Mexico.

King and Robinson hypothesized that Tamaulipa azurea is closely related to Conoclinium; B. L. Turner (1972) observed that it may be closer to Chromolaena.