boo·jum or boo·jum tree 
(bjəm)
(bjəm)n.
A deciduous tree (Fouquieria columnaris) native to northern Mexico and found chiefly in Baja California, having a thick tapering columnar trunk, slender spiny branches, and yellow flowers.
[After the Boojum, an imaginary character in the poem The Hunting of the Snark by Lewis Carroll.]
boojumFouquieria columnaris