About Helianthus nuttallii Torr. & A.Gray
Helianthus nuttallii, commonly called Nuttall's sunflower, is a sunflower species native to northern, central, and western North America. Its native range extends from Newfoundland west to British Columbia, and south to Missouri, New Mexico, and California. This is a herbaceous perennial plant that grows 50–400 cm (20–160 inches) tall. Its leaves are arranged oppositely on the lower section of the stem, and alternately higher up on the stem. The leaves are narrow and lanceolate, 8–20 cm (3.2–8.0 inches) long and 6–30 mm wide, with a rough texture. The species produces yellow flowers in flowerheads approximately 9 cm (3.6 inches) in diameter. Each flowerhead holds 10–20 ray florets and at least 60 disc florets, and each stem bears one to a few flowerheads. There are three recognized subspecies of Helianthus nuttallii. First is Helianthus nuttallii subsp. nuttallii, which is distributed across Canada and the western United States. This taxon is classified by some authorities as a synonym of the full Helianthus nuttallii species, while other authorities consider it a distinct subspecies. It belongs to the genus Helianthus within the family Asteraceae. Second is Helianthus nuttallii subsp. parishii (A.Gray) Heiser, commonly called the Los Angeles sunflower. This subspecies is endemic to Southern California, and it has been presumed extinct since 1937. Third is Helianthus nuttallii subsp. rydbergii (Britton) R. Long, which is distributed in central Canada and the interior northwestern United States.
