alyssum vs crucifer

alyssum and crucifer both are nouns.

Word	Noun	Adjective	Verb	Adverb
alyssum	Yes	No	No	No
crucifer	Yes	No	No	No

As nouns, crucifer is a hypernym of alyssum; that is, crucifer is a word with a broader meaning than alyssum:

alyssum: any garden plant of the genus Alyssum having clusters of small yellow or white flowers
crucifer: any of various plants of the family Cruciferae

Other hypernyms of alyssum include cruciferous plant.

alyssum (noun)	crucifer (noun)
any garden plant of the genus Alyssum having clusters of small yellow or white flowers	any of various plants of the family Cruciferae