Proc. Amer. Acad. Arts 6: 541. 1866.
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.
Varieties 5 (5 in the flora).
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.
|1||Phyllaries glabrous or sparsely hairy, densely glandular||> 2|
|1||Phyllaries strigoso- to hispido-hirsute, sometimes slightly glandular||> 3|
|2||Plants usually 12–40 or 30–60 cm; stems ascending-erect; leaves usually 15–35 mm||Erigeron breweri var. breweri|
|2||Plants 7–15 cm; stems prostrate to procumbent or decumbent; leaves 5–12 mm||Erigeron breweri var. jacinteus|
|3||Plants 20–30 cm; stems often wiry and brittle; phyllaries hispido-hirsute (hairs translucent, spreading, stiff, relatively thick-based), glandular||Erigeron breweri var. porphyreticus|
|3||Plants (30–)40–75 cm; stems not wiry or brittle; phyllaries strigoso- or hispido-hirsute (hairs ascending to ascending-appressed, white), eglandular||> 4|
|4||Phyllaries strigoso-hirsute (hairs relatively thin-based, ascending-appressed, gradually and slightly reduced in density from outer to inner phyllaries), eglandular||Erigeron breweri var. bisanctus|
|4||Phyllaries hispido-hirsute (hairs relatively thick-based, ascending, dense on outermost phyllaries, much less so on mid and inner), eglandular||Erigeron breweri var. covillei|