The Collaborative International Dictionary of English v.0.48:

cirio \cirio\ n.
   the candlewood of Mexico and couthwestern California (Idria
   columnaris or Fouquieria columnaris), having tall columnar
   stems and bearing honey-scented creamy yellow flowers; --
   called also the boojum tree.

   Syn: boojum tree, Fouquieria columnaris, Idria
        columnaris.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

boojum tree
    n 1: candlewood of Mexico and southwestern California having
         tall columnar stems and bearing honey-scented creamy yellow
         flowers [syn: boojum tree, cirio, Fouquieria
         columnaris, Idria columnaris]