Xanthisma spinulosum var. chihuahuanum
Sida 20: 1408. 2003.
Perennials, 30–50 cm, often woody at base. Stems stiffly erect, usually much branched in proximal 1/2–2/3; mid internodes 2–5 mm. Leaves numerous, concentrated in proximal ± 1/2, spreading to loosely ascending, often much reduced distally, margins of proximal pinnatifid to 2-pinnatifid, of distal coarsely dentate to ± entire, lobes linear to lanceolate, 3–5 mm, faces usually hairy, rarely glabrous, often densely stipitate-glandular. Heads 2–10+ in diffuse arrays. Peduncles relatively terminal and lateral, 0.5–2 cm. Involucres 12–15 mm wide. 2n = 8, 16.
Phenology: Flowering spring–fall.
Habitat: Clayey to rocky washes, prairies, plains, roadsides
Elevation: 1000–1800 m
Ariz., N.Mex., Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (Sonora)
Variety chihuahuanum is a Chihuahuan Desert taxon that extends into the southern United States.
"spreading" is not a number.