Source : Webster's Revised Unabridged Dictionary (1913)

Mahon stock \Ma*hon" stock`\ (Bot.)
   An annual cruciferous plant with reddish purple or white
   flowers ({Malcolmia maritima}). It is called in England
   {Virginia stock}, but the plant comes from the Mediterranean.

Source : WordNet®

Malcolmia maritima
     n : erect branching herb cultivated for its loose racemes of
         fragrant white or pink or red or lilac flowers; native to
         sands and sea cliffs of southwestern Greece and southern
         Albania [syn: {Virginian stock}, {Virginia stock}]