The Collaborative International Dictionary
Sphaerospore
Sphaerospore \Sph[ae]"ro*spore\, n. [Gr. ???? sphere + E. spore.] (Bot.) One of the nonsexual spores found in red alg[ae]; a tetraspore.
Wiktionary
sphaerospore
n. (context botany English) One of the non-sexual spores found in red algae; a tetraspore.