Annuals, biennials, or short-lived perennials, ( subshrubs in var. ziegleri). Stems, branches, and peduncles glabrous, puberulent, or canescent, sometimes also stipitate-glandular or gland-dotted. Leaf blades linear-lanceolate to linear or linear-oblanceolate (ovate to obovate in var. leucanthemifolia), mid 10-60 × 1.5-6(-8) mm, margins entire to irregularly dentate or serrate, faces glabrous, puberulent, or canescent, sometimes sparsely stipitate-glandular; distal bases not clasping or slightly clasping (clasping in var. leucanthemifolia). Involucres campanulate or turbinate. Phyllaries in 3-10 series, appressed, spreading, or reflexed, indurate bases usually glabrous, apices acute to acuminate, 1-3 mm, herbaceous, faces glabrous (indurate bases, sometimes foliaceous parts) or hairy (only foliaceous parts), sometimes stipitate-glandular. Receptacles 2.5-5 mm diam. Ray florets pistillate and fertile, or sterile or 0 (in var. shastensis); laminae white, blue, or purple, 6-12 × 1-3 mm. Disc florets: corollas 4-6(-7) mm. Cypselae glabrous or moderately appressed-hairy.
Plant: Annual to perennial herb < 12 dm, generally canescent-puberulent and often glandular; stems 1-several from base, generally branched above and ± bushy Leaves: simple, alternate, generally 3-10 cm, generally 2-6 mm wide, linear to obovate, subentire to dentate or minutely serrate; lower tapered; upper sometimes clasping INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate; phyllaries generally in 3-10 series, tips short-triangular to elongate, acuminate, spreading to bent backward, generally ± glandular or glabrous Flowers: Ray flowers many (0 in var. shastensis ); corollas blue-purple; ligules 1-2 cm; Disk flowers many; corollas 5.5-8 mm, yellow; style tips triangular to linear, acute Fruit: achenes, 2.5-3.5 mm, narrowly obovate, weakly curved and ± flattened with 5-7 ribs on each face, glabrous or ± silky; pappus 6-8 mm Misc: 300-3400 m.