The Collaborative International Dictionary of English v.0.48:

goose-grass \goose-grass\ n. (Bot.),
   A low-growing perennial (Potentilla anserina) having leaves
   silvery beneath; foundin Northern U. S., Europe, and Asia.

   Syn: silverweed, goose-tansy, Potentilla anserina.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Silverweed \Sil"ver*weed`\, n. (Bot.)
   A perennial rosaceous herb (Potentilla Anserina) having the
   leaves silvery white beneath.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Potentilla anserina
    n 1: low-growing perennial having leaves silvery beneath;
         northern United States; Europe; Asia [syn: silverweed,
         goose-tansy, goose grass, Potentilla anserina]