The Collaborative International Dictionary
Hare's-tail \Hare's"-tail`\ (-t[=a]l`), n. (Bot.) A kind of grass ( Eriophorum vaginatum). See Cotton grass, under Cotton.
Hare's-tail grass (Bot.), a species of grass ( Lagurus ovatus) whose head resembles a hare's tail.
Wikipedia
Lagurus is a genus of Old World plants in the grass family, native to the Mediterranean Basin and nearby regions, from Azores and the Canary Islands to Crimea and Saudi Arabia. It is also naturalized in Australia, New Zealand, Ireland and Great Britain, and scattered locations in the Americas. The only known species is Lagurus ovatus, commonly called hare's-tail, hare's-tail grass or bunnytail. It is also grown as an ornamental plant for its attractive flower panicles.