The Collaborative International Dictionary of English v.0.48:

Prickly ash \Prickly ash\ (Bot.),
   1. A prickly shrub (Xanthoxylum Americanum) with yellowish
      flowers appearing with the leaves; also called toothache
      tree. All parts of the plant are pungent and aromatic.
      The southern species is Xanthoxylum Carolinianum.
      --Gray.
      [1913 Webster]

   2. (Bot.), Hercules'-club, also called the Angelica tree.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Angelica \An*gel"i*ca\, n. [NL. See Angelic.] (Bot.)
   1. An aromatic umbelliferous plant (Archangelica
      officinalis or Angelica archangelica) the leaf stalks
      of which are sometimes candied and used in confectionery,
      and the roots and seeds as an aromatic tonic.
      [1913 Webster]

   2. The candied leaf stalks of angelica.
      [1913 Webster]

   Angelica tree, a thorny North American shrub (Aralia
      spinosa), called also Hercules' club.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Hercules'-club \Hercules'-club\, Hercules'-club
\Hercules'-club\, Hercules-club \Hercules-club\prop. n.
   1. (Bot.) A densely spiny ornamental tree (Zanthoxylum
      clava-herculis) of the rue family, growing in southeast
      U. S. and West Indies. [WordNet sense 1]

   Note: It belongs to the same genus as one of the trees
         (Zanthoxylum Americanum) called prickly ash.

   Syn: Hercules'-clubs, Hercules-club, Zanthoxylum
        clava-herculis.
        [1913 Webster + WordNet 1.5]

   2. A small, prickly, deciduous clump-forming tree or shrub
      (Aralia spinosa) of eastern U.S.; also called Angelica
      tree and prickly ash. [WordNet sense 2]

   Syn: American angelica tree, devil's walking stick, Aralia
        spinosa.
        [1913 Webster + WordNet 1.5]

   3. A variety of the common gourd (Lagenaria vulgaris). Its
      fruit sometimes exceeds five feet in length.
      [1913 Webster]