Annual or perennial herbs, with simple entire clasping or perfoliate leaves, and compound umbels of yellow or greenish-yellow flowers. Involucre none in our species. Involucels of 5 ovate mucronate bracts. Calyx-teeth obsolete. Petals broad, the apex inflexed or infolded. Stylopodium conic. Styles short. Fruit oblong or oval, somewhat compressed laterally. Carpels angled, with slender equal ribs; oil-tubes none in our species. Seed-face concave. [Greek, ox-ribbed, referring to the leaves.]

About 65 species of wide geographic distribution Besides the following another occurs in the Rocky Mountains and northwestern America. Type species: Bupleurum rigidum L.

1. Bupleurum Rotundifòlium L. Hare's Ear. Thorough-Wax Or -Wort. Modesty

Fig. 3133

Bupleurum rotundifolium L. Sp. Pl. 236. 1753.

Annual, erect, rather stiff, branching, glabrous, pale, 1°-2° high. Leaves broadly ovate, or oval, mostly obtuse, mucronate, 1' - 1 1/2' long, perfoliate, or the lowest narrowed into a petiole; umbels terminal, 3-6-rayed, the rays seldom over 4" long; bracts of the involucels about as long as the rays, yellowish; fruit glabrous, about 1 1/2" long.

In cultivated fields, New Hampshire to North Carolina, west to South Dakota, Tennessee, Kansas and Arizona. Naturalized from Europe. July-Aug.

Bupleurum Odontites L., also European, with narrowly linear leaves, is recorded as found in Massachusetts.