CUPPLANT, Silphium perfoliatum L. 1, upper portion of plant; 2, ray flower. Perennial, reproducing by seed. Stem stout, square, erect, 4 to 8 feet (1.2 to 2.4 m) tall, branching slightly at the top. Leaves opposite, bases extending around stem to form a cup, rough on both sides, with saw toothed edges. Larger leaves 6 to 12 inches (15 to 30 cm) long, 4 to 8 inches (10 to 20 cm) wide. Flower heads 2 to 3 inches (5 to 7.5 cm) across, composed of bright yellow ray flowers surrounding yellow disk flowers. Seeds gray to black, oblong, flat, notched at end. Found in fence rows, roadsides, waste places. Does not persist in cultivated land. Also known as cup rosinweed.