About Helianthus silphioides Nutt.
Helianthus silphioides Nutt. is a North American sunflower species, commonly called rosinweed sunflower or Ozark sunflower. It is native to the central United States, with its primary distribution in the Ozarks and the Tennessee Valley. Additional populations exist as far north as Kentucky and Illinois, and as far south as Louisiana, Mississippi, and Alabama. This species grows in open locations. It is a perennial herb that can reach up to 300 cm (10 feet) in height. Its leaves are broadly egg-shaped. A single plant usually produces between 3 and 15 flower heads. Each flower head holds 8 to 13 yellow ray florets, which surround 75 or more red disc florets. A 2004 conservation assessment from Illinois lists Helianthus silphioides as critically imperiled within the state. It is also considered endangered within Kentucky, a status that is likely due to habitat loss of open oak woodlands and barrens. Across the rest of its range, the species is classified as apparently secure, or its conservation status has not been determined.
