The Collaborative International Dictionary of English v.0.48:

bladderpod \blad"der*pod\ n.
   1. a North American wild lobelia (Lobelia inflata) having
      small blue flowers and inflated capsules formerly used as
      an antispasmodic.

   Syn: Indian tobacco.
        [WordNet 1.5]

   2. any of a number of annual or perennial herbs with inflated
      seed pods; some are placed in the genus Lesquerella.
      [WordNet 1.5]

   3. any of several plants of the genus Physaria having
      racemose yellow flowers and inflated pods.
      [WordNet 1.5]

   4. any of several hairy North American herbs having yellow
      racemose flowers and inflated pods.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

bladderpod
    n 1: North American wild lobelia having small blue flowers and
         inflated capsules formerly used as an antispasmodic [syn:
         Indian tobacco, bladderpod, Lobelia inflata]
    2: annual or perennial herbs with inflated seed pods; some
       placed in genus Lesquerella
    3: any of several plants of the genus Physaria having racemose
       yellow flowers and inflated pods
    4: any of several hairy North American herbs having yellow
       racemose flowers and inflated pods