Source : Webster's Revised Unabridged Dictionary (1913)

Richweed \Rich"weed`\, n. (Bot.)
   An herb ({Pilea pumila}) of the Nettle family, having a
   smooth, juicy, pellucid stem; -- called also {clearweed}.

Source : WordNet®

clearweed
     n : a plants of the genus Pilea having drooping green flower
         clusters and smooth translucent stems and leaves [syn: {richweed},
          {dead nettle}, {Pilea pumilla}]