Similar in appearance to the Black-eyed Susan (Rudbeckia hirta), but more branched and with smaller heads of flowers. It is rather tall, 2 to 5 feet high with rough and pubescent stems but scarcely hairy. Leaves thin, rough on both surfaces, bright green and the lower at least three-lobed, 2 to 4 inches long, one-half to 1 inch wide. Heads about 2 inches broad, numerous, in terminal corymbs. Ray flowers bright yellow, sometimes orange or orange-purple at the base, eight to twelve in number; disk flowers purple, forming an ovoid center to the head, about one-half of an inch broad. Bracts of the involucres linear, pubescent and reflexed.
In moist soil, southern New York to Georgia, west to Michigan, Minnesota, Missouri, Kansas and Louisiana. Flowering from June to October.
Memoir 15 N. Y. State Museum
Thin-Leaved Coneflower - Rudbeckia triloba