Source : Webster's Revised Unabridged Dictionary (1913)

Mechoacan \Me*cho"a*can\, n.
   A species of jalap, of very feeble properties, said to be
   obtained from the root of a species of {Convolvulus} ({C.
   Mechoacan}); -- so called from Michoacan, in Mexico, whence
   it is obtained.

Convolvulus \Con*vol"vu*lus\, n.; pl. L.{Convolvuli}, E.
   {Convoluluses}. [L., bindweed, fr. convolvere to roll around.
   So named from its twining stems.] (Bot.)
   A large genus of plants having monopetalous flowers,
   including the common bindweed ({C. arwensis}), and formerly
   the morning-glory, but this is now transferred to the genus
   {Ipom[ae]a}.

         The luster of the long convolvuluses That coiled around
         the stately stems.                       --Tennyson.

Source : WordNet®

convolvulus
     n : any of numerous plants of the genus Convolvulus
     [also: {convolvuli} (pl)]