Tall or beardless chinchweed

Perennials, 30–120 cm (caudices woody, 2–8+ mm diam.); herbage unscented. Stems erect, glabrous. Leaves narrowly linear, 10–50 × 1–2 mm (sometimes smaller, bractlike distally), margins with 0–1 pairs of setae, faces glabrous (abaxial dotted near each margin with a row of elliptic oil-glands ca. 0.3 mm). Heads borne singly or in open, cymiform arrays. Peduncles 10–80 mm. Involucres cylindric. Phyllaries distinct, linear-oblong, 5–9.5 × 1–1.5 mm (each dotted with 1–2 swollen, subapical oil-glands and a row of 2–3 linear, submarginal oil-glands on each side of midrib). Ray florets 5; corollas 6–11 mm (laminae often dotted near margins with inconspicuous oil-glands). Disc florets 4–7; corollas 3.7–6 mm (lobes 5, equal, each with 1 subterminal oil-gland). Cypselae 3.5–5 mm, puberulent (hair tips blunt); pappi of 1–3 stout awns 1–2 mm or coroniform. 2n = 24.

Flowering Aug–Oct. Pine-oak-juniper woodlands, grasslands, arid shrublands; 1000–1700 m; Ariz.; Mexico (Chihuahua, Sonora).

Pectis imberbis occurs in relatively small, widely separated populations. Overgrazing may be a factor in the scarcity of these plants. They are generally more than 25 cm before they begin to flower and may be unable to reproduce under grazing pressure.