epiphyllum vs orchid cactus

epiphyllum and orchid cactus both are nouns.

Word	Noun	Adjective	Verb	Adverb
epiphyllum	Yes	No	No	No
orchid cactus	Yes	No	No	No

As nouns, epiphyllum and orchid cactus are synonyms defined as:

epiphyllum and orchid cactus: any cactus of the genus Epiphyllum having flattened jointed irregularly branching stems and showy tubular flowers

epiphyllum (noun)	orchid cactus (noun)
any cactus of the genus Epiphyllum having flattened jointed irregularly branching stems and showy tubular flowers	any cactus of the genus Epiphyllum having flattened jointed irregularly branching stems and showy tubular flowers