The Collaborative International Dictionary of English v.0.48:

jack-in-the-pulpit \jack-in-the-pulpit\ n.
   1. A common American spring-flowering woodland herb
      (Aris[ae]ma triphyllum) having sheathing leaves and an
      upright club-shaped spadix with overarching green and
      purple spathe producing scarlet berries; also called
      Indian turnip.

   Syn: Indian turnip, wake-robin, Arisaema triphyllum,
        Arisaema atrorubens.
        [WordNet 1.5]

   2. A common European arum (Arum maculatum) with lanceolate
      spathe and short purple spadix; it emerges in early spring
      and is a source of a sagolike starch called arum.

   Syn: cuckoo-pint, cuckoopint, lords and ladies,
        lords-and-ladies, Arum maculatum.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

jack-in-the-pulpit
    n 1: common American spring-flowering woodland herb having
         sheathing leaves and an upright club-shaped spadix with
         overarching green and purple spathe producing scarlet
         berries [syn: jack-in-the-pulpit, Indian turnip, wake-
         robin, Arisaema triphyllum, Arisaema atrorubens]
    2: common European arum with lanceolate spathe and short purple
       spadix; emerges in early spring; source of a starch called
       arum [syn: cuckoopint, lords-and-ladies, jack-in-the-
       pulpit, Arum maculatum]