The Collaborative International Dictionary of English v.0.48:

Physostigmine \Phy`so*stig"mine\, n. (Chem.)
   An alkaloid found in the Calabar bean (the seed of
   Physostigma venenosum), and extracted as a white,
   tasteless, substance, amorphous or crystalline; -- formerly
   called eserine, with which it was regarded as identical.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Calabar \Cal"a*bar\, n.
   A district on the west coast of Africa.
   [1913 Webster]

   Calabar bean, The of a climbing legumious plant
      (Physostigma venenosum), a native of tropical Africa. It
      is highly poisonous. It is used to produce contraction of
      the pupil of the eye; also in tetanus, neuralgia, and
      rheumatic diseases; -- called also ordeal bean, being
      used by the negroes in trials for witchcraft.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Eserine \Es"er*ine\ (?; 104), n. [From native name of the
   Calabar bean: cf. F. ['e]s['e]rine.] (Chem.)
   An alkaloid found in the Calabar bean, and the seed of
   Physostigma venenosum; physostigmine. It is used in
   ophthalmic surgery for its effect in contracting the pupil.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Physostigma venenosum
    n 1: tropical African woody vine yielding calabar beans [syn:
         calabar-bean vine, Physostigma venenosum]