The fine foliage of succulents are popular accents to dry gravel gardens as well as mini indoor gardens that all the craze in space-lacking Japanese cities and cramp homes.
Aeomium from the crassulaceae family, northern Africa (thanks Cheri)
What we commonly call “epiphyllums” today are actually hybrids of epiphytic cacti species native to the jungles of Central and South America, as well as Mexico. The word epiphyllum in Greek means “upon the leaf” and the flowers appear to bloom directly on the leaves. Jungle cacti, however, have no leaves; their leaf-like parts are actually thickened stems or branches. These stems are typically flat but often grow in a triangular shape. Unlike most desert cacti, epiphyllums are not covered with spines. They do, however, have hair bristles or tiny spines in the areolas, some more so than others.
It was in the tropical jungles of the New World that European explorers discovered epiphytic cacti. In their native habitat, the epiphytic species often grow in the forks of trees or in rock crevices where their small, fibrous roots take hold in decaying vegetative matter. Some epiphytic species are rooted in the ground and use aerial roots to climb up tree trunks. The plants can draw moisture from the humid air and tropical rains.
In 1813 Englishman Adrian H. Haworth first described Epiphyllum phyllanthus and thus established the name Epiphyllum as a valid name for a Genus. However, in 1820, Link, in Germany, described the same plant as Phyllocactus phyllanthus, unaware that Haworth had already described the plant. Since Epiphyllum phyllanthus was the first name published, Epiphyllum became the valid name for this genus and phyllocactus became a synonym for epiphyllum. In fact, phyllocactus became established as a word to describe not only the epiphyllum species, but all epiphytic cacti including the hybrids produced by various epiphytic cacti plants.
There is some belief that American nurserymen in the early 1900’s did not like the name “phyllocactus”, but preferred “epiphyllum” and either didn’t know or didn’t care that in Germany “epiphyllum” did not describe all epiphytic cacti and their hybrids. Perhaps they just “assumed” that “epiphyllum” and “phyllocactus” were completely synonymous.
While most everyone agrees that our hybrid plants aren’t all Epiphyllum hybrids, the real discussion today is “What is the most accurate word to call our plants?”
There are many suggestions: epiphyllum (with a lower case “e”), epicactus, phyllocactus, epi, or Epiphyllum Hort. (or even Epiphyllum Hort. non Haworth).
Those who prefer epiphyllum feel that a lower case “e” and not italicized or underlined is acceptable. Since “epi” means “upon” and “phyllum” means “leaf”, it makes sense to call these “man-arranged hybrids” epiphyllums because they produce flowers on leaf-like stems.
Others feel that epicactus is best; however, some feel that this would not be completely accurate because epicactus also includes other epiphytic cacti including Schlumbergera and Rhipsalidopsis hybrids.
Epi is what most members call the plants; rarely do you hear society members using the complete “epiphyllum” in conversation. This may be too casual for some.
Epiphyllum Hort. means “Epiphyllum as used by hobbyists” or in other words, hybrids. This is probably the most accurate of all the choices; however, it’s a bit awkward for conversation and casual writing.
The term “orchid cactus” is almost completely dismissed as the plants are not related to orchids in any way.
Until there is a consensus among the experts, SDES has elected to continue as it has been. In our publications we will use epiphyllum (lower case “e”, no italics) and epi. Although there has been talk among other epi societies about changing their names, at this time SDES will remain the San Diego Epiphyllum Society, Inc.
Source from San Diego Epiphyllum Society, Inc.
For photos of varieties of epi or epiphyllum, see http://davesgarden.com/forums/f/episetc/all/