true guava vs Psidium guajava

true guava and Psidium guajava both are nouns.

Word	Noun	Adjective	Verb	Adverb
true guava	Yes	No	No	No
Psidium guajava	Yes	No	No	No

As nouns, true guava and Psidium guajava are synonyms defined as:

true guava and Psidium guajava: small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit

Other synonyms of true guava include guava, guava bush.

true guava (noun)	Psidium guajava (noun)
small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit	small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit