The Collaborative International Dictionary of English v.0.48:

Flyaway grass \Flyaway grass\ (Bot.)
   The hair grass (Agrostis scabra). So called from its light
   panicle, which is blown to great distances by the wind.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Hair grass \Hair" grass`\ (gr[.a]s`). (Bot.)
   A grass with very slender leaves or branches; as the
   Agrostis scabra, and several species of Aira or
   Deschampsia.
   [1913 Webster]