rhodosperm

from The Collaborative International Dictionary of English v.0.48

Rhodosperm \Rho"do*sperm\, n. [Gr. "ro`don the rose + spe`rma a
   seed.] (Bot.)
   Any seaweed with red spores.
   [1913 Webster]

   Note: As the name of a subclass, Rhodosperms, or
         {Rhodospermeae}, is synonymous with {Florideae} (which
         see.)
         [1913 Webster]