Plants 30-150 cm, herbage glabrous. Stems usually 1, erect. Leaf blades 40-100 mm, bases narrowly decurrent, margins entire to spinulose-toothed, faces resinous. Heads usually in tight to loose, corymbiform arrays, rarely borne singly. Peduncles: ultimate 1-40 mm, minutely stipitate-glandular. Phyllaries minutely stipitate-glandular. Ray corollas 4-11 mm. Pappi (ray) 0, outer disc 0 or minute crowns, inner nearly 0 or minute crowns, sometimes lacerate or with awnlike scales 0.2-0.8 mm, rarely with ring of persistent, 15-20, antrorsely ciliolate bristles ca. 1.4 mm. 2n = 12. Flowering (Jul-)Aug-Oct. Meadows, stream bottoms, ditches, grasslands, areas of oak-pine or pine woodlands, usually in habitats at least intermittently wet; 1100-2700 m; Ariz., Tex.; Mexico (Chihuahua, Durango, Jalisco, Sonora, Zacatecas).

Plant: Robust taprooted annual to 2 m in moist areas; herbage glutinous Leaves: leaves alternate, linear to lance-oblong