silver fern vs Pityrogramma argentea

silver fern and Pityrogramma argentea both are nouns.

Word	Noun	Adjective	Verb	Adverb
silver fern	Yes	No	No	No
Pityrogramma argentea	Yes	No	No	No

As nouns, silver fern and Pityrogramma argentea are synonyms defined as:

silver fern and Pityrogramma argentea: fern of southern tropical Africa having fronds with white undersides

silver fern (noun)	Pityrogramma argentea (noun)
fern of southern tropical Africa having fronds with white undersides	fern of southern tropical Africa having fronds with white undersides
tropical American fern having fronds with white undersides