Florideae \Flo*rid"e*[ae]\, prop. n. pl. [NL., from L. flos, floris, a flower.] (Bot.) A subclass of alg[ae] including all the red or purplish seaweeds; the Rhodosperme[ae] of many authors; -- so called from the rosy or florid color of most of the species. [1913 Webster]
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]