silverweed

from WordNet (r) 3.0 (2006)

silverweed
    n 1: any of various twining shrubs of the genus Argyreia having
         silvery leaves and showy purple flowers
    2: low-growing perennial having leaves silvery beneath; northern
       United States; Europe; Asia [syn: {silverweed}, {goose-
       tansy}, {goose grass}, {Potentilla anserina}]

from 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]