Perennials, 30-50+ cm; taprooted or ± rhizomatous (bases weakly creeping, horizontal to erect). Stems 1 or 2-5+, loosely clustered, glabrous or leaf axils sparsely tomentose. Basal leaves (and proximal cauline) petiolate; blades narrowly lanceolate (pinnatifid, lateral lobes 6+ pairs, their bases petioluliform, terminal lobes smaller than laterals), 60-100 × 10-20 mm, bases tapering, ultimate margins dentate. Cauline leaves gradually reduced (sessile). Heads 6-20+ in corymbiform arrays. Peduncles bracteate or ebracteate, glabrous. Calyculi inconspicuous. Phyllaries (13-)21, green (tips yellow), 4-6+ mm, glabrous. Ray florets (8-)13; corolla laminae 8-10+ mm. Disc florets 40-55+; corolla tubes 2-3 mm, limbs 2-3 mm. Cypselae 1-1.5 mm, hirtellous on ribs; pappi 3.5-4.5 mm.

Flowering late Mar-early Jun. Streambeds, openings in wooded areas on limestone-derived soils or on igneous-derived soils that are damp during growing season; 1400-2100 m; Tex.; Mexico (Chihuahua, Coahuila).

In the flora area, Packera millelobata occurs only in the trans-Pecos region of western Texas. It has been confused with P. tampicana. Their ranges overlap along the Rio Grande; P. millelobata has leaves with narrow terminal lobes; P. tampicana has terminal lobes as wide as the leaf blade. In addition, P. tampicana is annual with pronounced taproots; P. millelobata is perennial with taprooted caudices.