lactuca

from WordNet (r) 3.0 (2006)

Lactuca
    n 1: an herb with milky juice: lettuce; prickly lettuce [syn:
         {Lactuca}, {genus Lactuca}]

from The Collaborative International Dictionary of English v.0.48

Lactuca \Lac*tu"ca\, n. [L., lettuce. See {Lettuce}.] (Bot.)
   A genus of composite herbs, several of which are cultivated
   for salad; lettuce.
   [1913 Webster]