seed fern vs pteridosperm

seed fern and pteridosperm both are nouns.

Word	Noun	Adjective	Verb	Adverb
seed fern	Yes	No	No	No
pteridosperm	Yes	No	No	No

As nouns, seed fern and pteridosperm are synonyms defined as:

seed fern and pteridosperm: an extinct seed-producing fernlike plant of the order Cycadofilicales (or group Pteridospermae)

seed fern (noun)	pteridosperm (noun)
an extinct seed-producing fernlike plant of the order Cycadofilicales (or group Pteridospermae)	an extinct seed-producing fernlike plant of the order Cycadofilicales (or group Pteridospermae)