Black-eyed Susan is an annual or biennial herb in the Asteraceae family, belonging to the genus Rudbeckia. It grows to 30-100 cm tall. The stem is unbranched or sparingly branched above, covered with coarse hairs throughout. Lower leaves are long ovate, oblong, or spoon-shaped; upper leaves are lanceolate-oblong, with the tip gradually tapering, and edges with fine to coarse, sparsely spaced serrations or entire. The capitula are 5-7 cm in diameter, with long peduncles. The involucral bracts are broadly ovate in the outer layer; shorter, lanceolate-linear in the inner layer, with obtuse tips. The receptacle is conical; the scales are linear, folded into keel-like petals. The ray florets are bright yellow; the ligules are oblong, usually 10-14 in number. The disk florets are dark brown or dark purple. The achenes are quadrangular, dark brown, without pappus.