plant kingdom vs Plantae

plant kingdom and Plantae both are nouns.

Word	Noun	Adjective	Verb	Adverb
plant kingdom	Yes	No	No	No
Plantae	Yes	No	No	No

As nouns, plant kingdom and Plantae are synonyms defined as:

plant kingdom and Plantae: (botany) the taxonomic kingdom comprising all living or extinct plants

Other synonyms of plant kingdom include kingdom Plantae.

plant kingdom (noun)	Plantae (noun)
(botany) the taxonomic kingdom comprising all living or extinct plants	(botany) the taxonomic kingdom comprising all living or extinct plants