The Collaborative International Dictionary of English v.0.48:

Laminaria \Lam`i*na"ri*a\, n. [NL. See Lamina.] (Bot.)
   A genus of great seaweeds with long and broad fronds; kelp,
   or devil's apron. The fronds commonly grow in clusters, and
   are sometimes from thirty to fifty feet in length. See
   Illust. of Kelp.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Laminaria
    n 1: type genus of the family Laminariaceae: perennial brown
         kelps [syn: Laminaria, genus Laminaria]