308-277 BC CYRENAICA, CYRENE AR Didrachm

Silphium is a genus of North American plants in the tribe Heliantheae within the family Asteraceae.^[1][2]

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;^[3] this differs from sunflowers, where ray florets are sterile and disc florets are perfect, capable of producing both pollen and seeds.^[4]