Lophophora williamsii vs cactus

Lophophora williamsii and cactus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lophophora williamsii	Yes	No	No	No
cactus	Yes	No	No	No

As nouns, cactus is a hypernym of Lophophora williamsii; that is, cactus is a word with a broader meaning than Lophophora williamsii:

Lophophora williamsii: a small spineless globe-shaped cactus; source of mescal buttons
cactus: any succulent plant of the family Cactaceae native chiefly to arid regions of the New World and usually having spines

Lophophora williamsii (noun)	cactus (noun)
a small spineless globe-shaped cactus; source of mescal buttons	any succulent plant of the family Cactaceae native chiefly to arid regions of the New World and usually having spines