desert olive vs forestiera

desert olive and forestiera both are nouns.

Word	Noun	Adjective	Verb	Adverb
desert olive	Yes	No	No	No
forestiera	Yes	No	No	No

As nouns, forestiera is a hypernym of desert olive; that is, forestiera is a word with a broader meaning than desert olive:

desert olive: spiny branching deciduous shrub of southwestern United States having clusters of insignificant yellow-white flowers appearing before leaves followed by attractive black berrylike fruits
forestiera: any plant of the genus Forestiera

desert olive (noun)	forestiera (noun)
spiny branching deciduous shrub of southwestern United States having clusters of insignificant yellow-white flowers appearing before leaves followed by attractive black berrylike fruits	any plant of the genus Forestiera