Erect or ascending canescent branching herbs, with alternate leaves, and rather large heads of both tubular and radiate flowers, solitary at the ends of the branches. Involucre hemispheric, its bracts lanceolate or linear, scarious-margined, imbricated in a few series, the outer smaller. Receptacle convex or conic, naked. Ray-flowers pistillate, white or purplish.

Disk-flowers perfect, yellow, their corollas tubular, the limb expanded above, 5-dentate.

Anthers obtuse and entire at the base. Style-branches flattened, their appendages short, obtuse. Achenes many-ribbed. Pappus a short dentate crown. [Greek, faint-crown.]

About 5 species, natives of the southwestern United States and Mexico. Type species: Aphanostephus ramosissimus DC.

25 Aphanostephus Dc Prodr 5 310 1836 940

1. Aphanostephus Skirrobasis (Dc.) Tre-Lease. Aphanostephus

Fig. 4269

Keerlia skirrobasis DC. Prodr. 5: 310. 1836.

Leucopsidium arkansanum DC. Prodr. 6: 43. 1837.

Aphanostephus arkansanus A. Gray, Pl. Wright. 1: 93. 1852.

Aphanostephus skirrobasis Trelease; Coville & Bran-ner, Rep. Geol. Surv. Ark. 1884: Part 4, 191. 1891.

Erect, or diffusely branched, densely canescent, 6'-2° high. Basal and lower leaves spatulate, obtuse, 1'- 4' long, somewhat dentate, laciniate or entire, narrowed into margined petioles; upper leaves lanceolate, oblong or oblanceolate, obtuse or acute, mostly sessile, smaller; heads 8"-12" broad, 3"-5" high; rays numerous, narrow, entire; achenes ribbed and angled; pappus a lobed or dentate crown.

In dry soil, Kansas to Texas and Chihuahua, east to Florida. May-Aug.