It is often confused with the genus "Epiphyllum". The case of "Epiphyllum" is complex. The true genus "Epiphyllum" now has around 19 species. Epiphyllum oxypetalum is an easily cultivated, fast growing "Epiphyllum". He thought he had found a close relative to "Epiphyllum anguliger". This species was formerly placed in the genus "Epiphyllum" as "Epiphyllum anguliger". Propagating epiphyllum hybrids from cuttings is said to be easy. This is the most commonly grown of the "Epiphyllum" species. "E. laui" is most closely allied to Epiphyllum crenatum and Epiphyllum anguliger. The broad-leaved epiphyllum ("Epiphyllum oxypetalum") is particularly well-known. The genus "Epiphyllum" was created in 1812 by Haworth, based on Linnaeus's "Cactus phyllanthus". The others are "Disocactus speciosus" and "Epiphyllum crenatum". Epiphyllum hybrids need different treatment from semi-desert cacti. "Cactus phyllanthus" today - "Epiphyllum phyllanthus". This species is closely related to "Epiphyllum oxypetalum" and differs mainly in its smaller flowers.