The Collaborative International Dictionary of English v.0.48:

Gymnogen \Gym"no*gen\ (j[i^]m"n[-o]*j[e^]n), n. [Gr. gymno`s
   naked + -gen.] (Bot.)
   One of a class of plants, so called by Lindley, because the
   ovules are fertilized by direct contact of the pollen. Same
   as Gymnosperm.
   [1913 Webster]