From The Collaborative International Dictionary of English v.0.48 :
Juncus \Juncus\ n. The type genus of the Juncaceae, comprising the rushes; they are perennial tufted glabrous marsh plants of temperate regions. Syn: genus Juncus. [WordNet 1.5]From WordNet (r) 3.0 (2006) :
Juncus n 1: type genus of the Juncaceae; perennial tufted glabrous marsh plants of temperate regions: rushes [syn: Juncus, genus Juncus]