Vernonia lettermanni

Vernonia lettermanni Engelm.; A. Gray, Proc. Am Acad. 16: 78. 1880.
Cacalia Lettermannii Kuntze, Rev. Gen. 970. 1891.
Stems erect, 2-5 dm. tall; glabrous; leaves crowded, ascending, the blades linear, 3-6 cm. long, 1-3 mm. wide, somewhat revolute, glabrous, glandular-punctate beneath, 1-nerved; inflorescence terminal, compact, 2-5 cm. wide; heads crowded, 8-13-flowered; involucre cylindric or narrowly campanulate, about 8 mm. high; scales closely imbricate and appressed, purple, glabrous on the back, ciliate, the outer triangular and sharply acute, the inner oblong, acute or acuminate; achenes glabrous, resinous, 4-5 mm. long; pappus-bristles purple, 7 mm. long, the scales nearly white, 0.7 mm. long.
Type locality: Sandbars of the Washita, Arkansas.
Distribution: Arkansas and Oklahoma.