Source : Webster's Revised Unabridged Dictionary (1913)

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

Source : WordNet®

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