3. Spermolepis inermis (Nutt. ex DC.) Mathias & Constance (western scale-seed)

Pl. 212 a–c; Map 885

Stems 8–60 cm long, strongly ascending to erect. Leaf blades 1–5 cm long, oblong to oblong-ovate in outline. Rays 5–11, 1–13 mm long, unequal in length, strongly ascending, straight, the central umbellet of most umbels sessile or nearly so and 1–3-flowered. Flower stalks 1–6 mm long, the central umbellets often with the flowers sessile or nearly so. Ovaries and fruits glabrous and smooth or roughened with dense, minute tubercles. 2n=16. May–June.

Scattered in the western half of the state, uncommonly eastward to St. Louis, Scott, and Dunklin Counties (Illinois to Mississippi west to Nebraska and New Mexico, introduced farther east to North Carolina and Florida; Mexico). Sand prairies, upland prairies, and glades; also fallow fields, roadsides, and railroads.