Exorhiz[ae]

from The Collaborative International Dictionary of English v.0.48

Exorhiza \Ex`o*rhi"za\ ([e^]ks`[-o]*r[imac]"z[.a]), n.; pl.
   {Exorhiz[ae]} (-z[=e]). [NL. fr. Gr. 'e`xw outside + 'ri`za
   root.] (Bot.)
   A plant Whose radicle is not inclosed or sheathed by the
   cotyledons or plumule. --Gray. Exorhizal