The Collaborative International Dictionary of English v.0.48:
Laver \La"ver\ (l[=a]"v[~e]r), n.
The fronds of certain marine alg[ae] used as food, and for
making a sauce called laver sauce. Green laver is the Ulva
latissima; purple laver, Porphyra laciniata and Porphyra
vulgaris. It is prepared by stewing, either alone or with
other vegetables, and with various condiments; -- called also
sloke, or sloakan.
Mountain laver (Bot.), a reddish gelatinous alga of the
genus Palmella, found on the sides of mountains