hair grass

Short definition from Wiktionary

Noun

1. 1
   A grass with very slender leaves or branches, as: Agrostis scabra, a bunchgrass.
2. 2
   A grass with very slender leaves or branches, as: Several species of Aira.
3. 3
   A grass with very slender leaves or branches, as: Species of junegrass (Koeleria).
4. 4
   A grass with very slender leaves or branches, as: Several species of tussock grass (Deschampsia).