About Thymophylla pentachaeta (DC.) Small
Thymophylla pentachaeta, commonly called fiveneedle pricklyleaf, golden dyssodia, or dogweed, is a perennial or subshrub belonging to the daisy family Asteraceae. It reaches a maximum height of 20 centimetres, which is 8 inches. Its leaves are approximately 1.5 centimetres, or 1/2 inch, long, and have a pinnate divided structure. Flowering occurs from April to October. Its solitary yellow flower heads grow at the top of leafless stalks, and measure 13 millimetres, or 1/2 inch, across. Each flower head has 8 to 13 ray flowers surrounding a center of disk flowers. Compared to this species, the related Thymophylla acerosa is woodier, and bears leaves positioned closer to its flowers. Four varieties of Thymophylla pentachaeta are currently recognized: Thymophylla pentachaeta var. belenidium (DC.) Strother, Thymophylla pentachaeta var. hartwegii (A.Gray) Strother, Thymophylla pentachaeta var. pentachaeta, and Thymophylla pentachaeta var. puberula (Rydb.) Strother. This species is native to the southwestern and south-central United States, Mexico, and Argentina, where it occurs in arid climates.
