archegonium

from WordNet (r) 3.0 (2006)

archegonium
    n 1: a female sex organ occurring in mosses, ferns, and most
         gymnosperms

from The Collaborative International Dictionary of English v.0.48

Archegonium \Ar`che*go"ni*um\, n. [NL., fr. Gr. ? the first of a
   race.] (Bot.)
   The pistillidium or female organ in the higher cryptogamic
   plants, corresponding to the pistil in flowering plants.
   [1913 Webster]