A tall, perennial herb, with resinous juice. Stem usually smooth, square, branched above, 4 to 8 feet high. Leaves opposite, ovate or deltoid-ovate, the upper ones united around the stem, the lower leaves abruptly contracted into margined petioles. Rather thin in texture, usually rough on both surfaces, the margins coarsely angulate-dentate or the tipper ones often entire, the larger leaves 6 to 12 inches long and 4 to 8 inches wide. Heads numerous, yellow, nearly flat, 2 to 3 inches broad, composed of yellow ray flowers and disk flowers, the ray flowers twenty to thirty in number, each about 1 inch long and one-sixth of an inch wide, in two or three series. Outer bracts of the involucres broadly ovate, ciliolate, foliaceous and spreading.

Memoir 15 N. Y. State Museum

Plate 251

Cup Plant; Indian Cup   Silphium perfoliatum

Cup Plant; Indian Cup - Silphium perfoliatum

Moist soil, chiefly on prairies, southern Ontario to Minnesota and South Dakota, south to New Jersey, Georgia, Louisiana and Nebraska. Naturalized about New York City and in a few other localities in the east. Sometimes as an escape from cultivation.