The Collaborative International Dictionary of English v.0.48:

Salix \Sa"lix\, n.; pl. Salices. [L., the willow.] (Bot.)
   (a) A genus of trees or shrubs including the willow, osier,
       and the like, growing usually in wet grounds.
   (b) A tree or shrub of any kind of willow.
       [1913 Webster]