The Collaborative International Dictionary of English v.0.48:
Lyme grass \Lyme" grass`\n. (Bot.) A coarse perennial grass of several species of Elymus, esp. Elymus Canadensis, and the European Elymus arenarius. [1913 Webster]WordNet (r) 3.0 (2006):
Elymus arenarius n 1: a dune grass of the Pacific seacoast used as a sand binder [syn: sea lyme grass, European dune grass, Elymus arenarius, Leymus arenaria]