mustard tree vs genus Salvadora

mustard tree and genus Salvadora both are nouns.

Word	Noun	Adjective	Verb	Adverb
mustard tree	Yes	No	No	No
genus Salvadora	Yes	No	No	No

mustard tree (noun)	genus Salvadora (noun)
evergreen South American shrub naturalized in United States; occasionally responsible for poisoning livestock	genus of evergreen trees or shrubs; fruit is a drupe; grows in Africa through Arabia to India and China
glabrous or pubescent evergreen shrub or tree of the genus Salvadora; twigs are fibrous and in some parts of the world are bound together in clusters and used as a toothbrush; shoots are used as camel fodder; plant ash provides salt