gayfeather
/ˈɡeɪˌfɛðə/noun
Any of various bulbous plants of the genus Liatris (family Asteraceae), native to North American grassland, especially L. spicata, which has an erect spike of mauve flowers.
Origin
Mid 19th century; earliest use found in Sylvester Judd (1813–1853), novelist. From gay + feather, on account of the appearance of the flowers.