Source : Webster's Revised Unabridged Dictionary (1913)

Portulaca \Por`tu*la"ca\, n. [L., purslane.] (Bot.)
   A genus of polypetalous plants; also, any plant of the genus.

   Note: {Portulaca oleracea} is the common purslane. {P.
         grandiflora} is a South American herb, widely
         cultivated for its showy crimson, scarlet, yellow, or
         white, ephemeral blossoms.

Source : WordNet®

portulaca
     n : a plant of the genus Portulaca having pink or red or purple
         or white ephemeral flowers