The Collaborative International Dictionary of English v.0.48:

Myrtillocactus \Myrtillocactus\ prop. n.
   A small genus of arborescent cacti of Mexico and Central
   America.

   Syn: genus Myrtillocactus.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Myrtillocactus
    n 1: small genus of arborescent cacti of Mexico and Central
         America [syn: Myrtillocactus, genus Myrtillocactus]