Grindelia microcephala de Candolle var. adenodonta Steyermark, Ann. Missouri Bot. Gard. 21: 467. 1934

Annuals, 30–130 cm. Stems erect, stramineous to purple, proximally sparsely hirtellous to glabrate, distally ± hirtellous to villosulous. Cauline leaf blades ovate or ± triangular to oblong or obovate, 15–60(–90) mm, lengths 1.5–3(–4+) times widths, bases ± clasping, margins ± crenate (teeth 8–14 per cm, blunt, resin-tipped), apices obtuse to acute, faces usually hirtellous to scabridulous and glandular (glands usually in pits, sometimes sessile, seldom stipitate), sometimes glabrate. Heads in open, corymbiform to paniculiform arrays or borne singly. Involucres ± urceolate to hemispheric, 8–12 × 10–20 mm (usually subtended by leaflike bracts). Phyllaries in 4–6 series, spreading to appressed, lanceolate to linear, apices subulate, hooked to ± recurved or nearly straight, moderately resinous. Ray florets 20–27; laminae 8–12 mm. Cypselae stramineous or brownish, 3–4.5 mm, apices ± coronate to knobby, faces (outer) rugose (not transversely fissured; angles ± ribbed) or (inner) striate; pappi of 2 straight or weakly contorted, smooth (apices dilated), bristles or setiform awns 5–6 mm, equaling or surpassing disc corollas. 2n = 12.

Flowering (Jun–)Jul–Sep. Prairies, thickets, along streams; 10–200 m; Tex.