California coffee vs Rhamnus californicus

California coffee and Rhamnus californicus both are nouns.

Word	Noun	Adjective	Verb	Adverb
California coffee	Yes	No	No	No
Rhamnus californicus	Yes	No	No	No

As nouns, California coffee and Rhamnus californicus are synonyms defined as:

California coffee and Rhamnus californicus: evergreen shrub of western United States bearing small red or black fruits

Other synonyms of California coffee include California buckthorn, coffeeberry.

California coffee (noun)	Rhamnus californicus (noun)
evergreen shrub of western United States bearing small red or black fruits	evergreen shrub of western United States bearing small red or black fruits