资料来源 : Webster's Revised Unabridged Dictionary (1913)

Pillwort \Pill"wort`\, n. (Bot.)
   Any plant of the genus {Pilularia}; minute aquatic
   cryptograms, with small pill-shaped fruit; -- sometimes
   called {peppergrass}.

资料来源 : WordNet®

pillwort
     n : European water fern found around margins of bodies of water
         or in wet acid soil having small globose sporocarps [syn:
          {Pilularia globulifera}]