Black-eyed Susan (Rudbeckia hirta) belongs to Asteraceae (the Aster family). It is a perennial herb that is widely distributed in North America. This herb grows in sparse forests, grasslands, and wastelands, and up to 30-75 cm in height. The wholeplant is covered with coarse hair, rhombus-shaped bases, and conspicuous three veins. The upper leaves are lanceolate. The yellow flower-heads are 4 to 5 cm in diameter and bloom on the terminal branched stems from May to September. The tubular flowers are dark brown and arranged in spherical.