The Collaborative International Dictionary of English v.0.48:

beggar-lice \beggar-lice\ n.
   1. any of various Eurasian and North American plants having
      small prickly nutlets that stick to clothing.

   Syn: beggar's lice, beggar's-lice, beggar lice.
        [WordNet 1.5]

   2. any of various tropical and subtropical plants having
      trifoliate leaves and rough sticky pod sections or
      loments.

   Syn: tick trefoil, tick-trefoil, beggar's-lice.
        [WordNet 1.5]