rattail cactus vs rat's-tail cactus

rattail cactus and rat's-tail cactus both are nouns.

Word	Noun	Adjective	Verb	Adverb
rattail cactus	Yes	No	No	No
rat's-tail cactus	Yes	No	No	No

As nouns, rattail cactus and rat's-tail cactus are synonyms defined as:

rattail cactus and rat's-tail cactus: commonly cultivated tropical American cactus having slender creeping stems and very large showy crimson flowers that bloom for several days

Other synonyms of rattail cactus include Aporocactus flagelliformis.

rattail cactus (noun)	rat's-tail cactus (noun)
commonly cultivated tropical American cactus having slender creeping stems and very large showy crimson flowers that bloom for several days	commonly cultivated tropical American cactus having slender creeping stems and very large showy crimson flowers that bloom for several days