The Collaborative International Dictionary of English v.0.48:

morel \mor"el\, n. [See morelle.] (Bot.)
   1. Nightshade; -- so called from its blackish purple berries.
      [Written also morelle.]
      [1913 Webster]

   2. A kind of cherry. See Morello.
      [1913 Webster]

   Great morel, the deadly nightshade.

   Petty morel, the black nightshade. See Nightshade.
      [1913 Webster]

WordNet (r) 3.0 (2006):

petty morel
    n 1: unarmed woody rhizomatous perennial plant distinguished
         from wild sarsaparilla by more aromatic roots and panicled
         umbels; southeastern North America to Mexico [syn:
         American spikenard, petty morel, life-of-man, Aralia
         racemosa]