The Collaborative International Dictionary of English v.0.48:

Uredospore \U*re"do*spore\, n. (Bot.)
   The thin-walled summer spore which is produced during the
   so-called Uredo stage of certain rusts. See (in the
   Supplement) Uredinales, Heter[oe]cious, etc.
   [1913 Webster]