Source : Webster's Revised Unabridged Dictionary (1913)

Spinifex \Spin"i*fex\, n. [NL.; L. spina spine + facere to
   make.]
   1. (Bot.) A genus of chiefly Australian grasses, the seeds of
      which bear an elastic spine. {S. hirsutus} (black grass)
      and {S. longifolius} are useful as sand binders. {S.
      paradoxus}is a valuable perennial fodder plant. Also, a
      plant of this genus.

   2. Any of several Australian grasses of the genus
      {Tricuspis}, which often form dense, almost impassable
      growth, their leaves being stiff and sharp-pointed.