The Collaborative International Dictionary of English v.0.48:

Joint-fir \Joint"-fir`\, n. (Bot.)
   A genus (Ephedra) of leafless shrubs, with the stems
   conspicuously jointed; -- called also shrubby horsetail.
   There are about thirty species, of which two or three are
   found from Texas to California.
   [1913 Webster]