cystocarp

from The Collaborative International Dictionary of English v.0.48

Cystocarp \Cys"to*carp\ (s?s"t?-k?rp), n. [Gr. ???? bladder +
   karpo`s fruit.] (Bot.)
   A minute vesicle in a red seaweed, which contains the
   reproductive spores.
   [1913 Webster]