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]

The Collaborative International Dictionary of English v.0.48:

cuckoopint \cuck"oo*pint`\, cuckoo-pint \cuck"oo-pint`\n.
   a common European arum (Arum maculatum) with lanceolate
   spathe and short purple spadix; it emerges in early spring,
   and is the source of a sagolike starch called arum.

   Syn: cuckoopint, lords and ladies, lords-and-ladies,
        jack-in-the-pulpit, Arum maculatum.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Arum \A"rum\, n. [L. arum, aros, Gr. ?.]
   A genus of plants found in central Europe and about the
   Mediterranean, having flowers on a spadix inclosed in a
   spathe. The cuckoopint of the English is an example.
   [1913 Webster]

         Our common arums -- the lords and ladies of village
         children.                                --Lubbock.
   [1913 Webster]

   Note: The American "Jack in the pulpit" is now separated from
         the genus Arum.
         [1913 Webster]

WordNet (r) 3.0 (2006):

arum
    n 1: starch resembling sago that is obtained from cuckoopint
         root
    2: any plant of the family Araceae; have small flowers massed on
       a spadix surrounded by a large spathe [syn: arum, aroid]