About Helenium amarum (Raf.) H.Rock
Helenium amarum (Raf.) H.Rock is an annual herb species in the daisy family, with common names including yellowdicks, yellow sneezeweed, fiveleaf sneezeweed, and bitter sneezeweed. It is native to much of the south-central United States, specifically Texas, Oklahoma, Louisiana, Arkansas, and New Mexico, as well as northern Mexico, specifically Chihuahua and Coahuila. It also occurs as an introduced species in other parts of North America, Australia, and the West Indies. This plant is a multibranched, bushy, erect species that grows 20 to 70 centimeters, or 8 to 28 inches, tall. It is thickly covered with narrow to threadlike leaves. Daisy-like flower heads arranged in inflorescences grow at the tops of the plant's stem branches. Each flower head has a rounded center that can hold up to 250 golden yellow disc florets, surrounded by a fringe of 8 to 10 usually lighter yellow ray florets that curve backward away from the center. Its fruit is a tiny achene approximately one millimeter long. In some areas, this herb acts as a weed. Due to the presence of the lactone tenulin, the plant is somewhat toxic to mammals and insects. Two varieties of this species are recognized: Helenium amarum var. amarum native to the United States, and Helenium amarum var. badium Waterf. found in Oklahoma, Texas, Chihuahua, and Coahuila.
