blue gum vs Eucalyptus globulus

blue gum and Eucalyptus globulus both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue gum	Yes	No	No	No
Eucalyptus globulus	Yes	No	No	No

As nouns, blue gum and Eucalyptus globulus are synonyms defined as:

blue gum and Eucalyptus globulus: tall fast-growing timber tree with leaves containing a medicinal oil; young leaves are bluish

Other synonyms of blue gum include fever tree.

blue gum (noun)	Eucalyptus globulus (noun)
tall fast-growing timber tree with leaves containing a medicinal oil; young leaves are bluish	tall fast-growing timber tree with leaves containing a medicinal oil; young leaves are bluish