spore case vs spore sac

spore case and spore sac both are nouns.

Word	Noun	Adjective	Verb	Adverb
spore case	Yes	No	No	No
spore sac	Yes	No	No	No

As nouns, spore case and spore sac are synonyms defined as:

Other synonyms of spore case include sporangium.

spore case (noun)	spore sac (noun)
organ containing or producing spores	organ containing or producing spores
specialized leaf branch in certain aquatic ferns that encloses the sori or clusters of sporangia