The Collaborative International Dictionary
Lyme grass
Lyme grass \Lyme" grass`\n. (Bot.) A coarse perennial grass of several species of Elymus, esp. Elymus Canadensis, and the European Elymus arenarius.
Wiktionary
lyme grass
n. (taxlink Leymus arenarius species noshow=1), a coarse perennial grass.
WordNet
lyme grass
n. a grass of the genus Elymus