Perennials, 7-75 cm; taprooted (taproots usually not collected, often weakly developed), roots and caudices woody, branches rhizomelike (3-15 cm; fibrous-rooted), relatively slender, leafless, ascending. Stems usually ascending, sometimes prostrate to procumbent or decumbent (var. jacinteus) (often purple, distal branches stiff, spreading-ascending), hispid (hairs spreading-deflexed, 0.1-0.4 mm), mostly eglandular. Leaves cauline; (ascending) blades narrowly oblong-lanceolate to narrowly obovate, 10-40 × 2-5 mm, margins entire, relatively evenly spaced and sized, hispid, mostly eglandular. Heads 1 or 2-5(-10) in loosely corymbiform arrays. Involucres mostly 4-6 × 9-14 mm. Phyllaries in 3-5 series (all but outermost with stramineous margins and distal, greenish-herbaceous, narrowly rhomboid areas), strigoso- to hispido-hirsute or essentially glabrous, densely minutely glandular. Ray florets 20-62; corollas white or pink, often drying blue, 4-7 mm, laminae weakly coiling. Disc corollas 3.5-5.5 mm (throats slightly indurate, not inflated). Cypselae 2-3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of (15-)20-35(-50) bristles.

Erigeron breweri is treated as a member of E. sect. Linearifolii in G. L. Nesom (1992b), where all of the varieties are mapped in detail.