Silphium

Silphium is a genus of North American plants in the tribe Heliantheae within the family Asteraceae. Members of the genus, commonly known as rosinweeds, are herbaceous perennial plants growing to 0.2 m (8 in) to more than 2.5 m (8 ft 2 in) tall, with yellow (rarely white) flowerheads that resemble sunflowers. In the rosinweeds, the ray florets in the head are female and the disc florets are male; this differs from sunflowers, where ray florets are sterile and disc florets are perfect, capable of producing both pollen and seeds. The name of the genus comes from the Ancient Greek word for a North African plant whose identity has been lost, though it is known its gum or juice was prized by the ancients as a medicine and a condiment....read more on Wikipedia.