the space required to complete this explanation requires two seperate posts. Read this section and then proceed to the second section just beneath. One important note before you read this post. I AM NOT a trained botanist. I make no claim to be a plant expert. I simply have enjoyed for many years scientifically studying the species I collect. All the material presented here has been obtained from personal communication with botanists and by reading and rereading their published material. The basis of this text has been reviewed by several qualified experts. But if you disagree, feel free. The material presented is based on scientific fact There is a discussion regarding some beautiful wild taken photographs currently on UBC and within that discussion can be found opinions and queries on the topic of natural variation within a species. Specifically on a beautiful Ecuadorian species known to science as Anthurium angamarcanum. If you haven't see Beth Campbell's beautiful photographs you should take the time to read her thread (Lorax) here: http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=40016 The topic of natural plant variation is often a "touchy" subject with plant collectors. Many simply refuse to believe that a plant species can have more than one leaf or spathe form. Well, science has known the facts of natural variation for hundreds of years! And it has been the topic of some very hot debates, especially in the early 19th century. Natural variation within a species is however now a very well known scientific subject and is written about frequently. The problem that occurs within the world of plant collectors is many collectors simply refuse to try to understand or accept the concept of variation. But variation is not limited to aroids. You can find it in the world of ferns, club mosses, Epiphyllum cactii and many, many species, especially those that are tropical. And tropical plants include a huge number of plants that are now kept as "house plants". If you have more than just a few plants in your personal collection, it is highly likely you possess some that are natural variations of the same species. And I'd be willing to bet you are calling some of them by different scientific names (assuming of course you have attempted to learn their scientific names)! i fully expect to receive some personal email on what I'm about to write. For some odd reason there are a few "experts" who read UBC who just love to tell me "you're wrong" but they rarely seem to do it on the forum. Their preferred method is to write a "hot" email and use some unkind comments. So, just to let you know, I'm ready for your mail right now, "let 'er rip". If you were to read my personal email you'd realize that more than a few people who read UBC believe I am totally nuts! I receive mail once or twice every week from someone (especially one individual in the SE United states) who attempt to tell me the concept of natural variation is crazy and they know for certain the scientific plant names they are using are "scientifically" correct. I regret to tell you, sometimes they are not! You are simply using "synonyms" of the same plant. I'm going to attempt to explain the subject of natural variation by using common species. Some of this you've likely read within my posts before. I tried to edit this down but it is necessary to divide it into two posts due to the limitations on world length used by UBC. Almost every single plant in the world has at least one synonym. So what is that? When a plant is correctly identified to science it is given a scientific name. If the identification is correct to the genus of the species that name becomes a basionym or base name. But even those plants can still have a "basionym" that is wrong as to genus. Here's an example: In the world of aroids any aroid was originally identified in the genus "Arum". When the Linnean system was devised there were few genera for aroids. In the 1700 and early 1800's all botanists thought the only genus name for an aroid was Arum so every plant went into that genus. But as botany progressed many botanists of that era began to learn there were many genera that contain aroids. So plants such as Arum hederaceum became correctly Philodendron hederaceum. The same has happened with Anthurium species, Xanthosoma species and many others. Botanists simply began to understand the world of aroids was much larger and complex than originally suspected. But collectors often do not like that approach! And more than once I've found posts or received mail which insists some plant is something other than what it is now known to be because that collector "read" the wrong name in some older text. I won't name the forum, but one other often has such discussions. Regrettably, one of those texts, which can be a great learning tool (the very popular plant guide Tropica by Mr. A. B. Graf) appears to be the source of much of this confusion. Mr. Graf did a wonderful thing by introducing us all to the world of tropical plants, but he was not a botanist! He was a collector. And his texts are filled with errors as to species name. Many are simply made up and do not exist in science. If you love Mr. Graf's books, use them. But also understand it has many errors and you must do further research before instantly accepting the names he gives. I am not sure why, but the current publishers refuse to change anything he wrote and simply do not update his texts to make them current with the world of today's botanical science. I spent years chasing a Philodendron he called Philodendron mandaianum. IT DOES NOT EXIST! I recently attempted to learn the species name of a still moderately juvenile plant within my personal collection and I received several responses including one from a taxonomist. However, although he was attempting to help, his answer was obviously wrong. Why? He suggested my plant was a variation of Philodendron hederaceum but by examining the plant I could determine that was not possible. Philodendron hederaceum always produces new leaves from a sheath. P. hederaceum always has short petioles. P. hederaceum has a vein that runs towards to the bottom of the leaf, and it is always a scandent climber growing close to the host tree. My plant has none of these features other than it grows relatively close to the host but is not scandent. The petioles are very long, at least 25cm (0 inches) It has every vein running at a 45 degree angle to the side of the blade. And it has more than double the leaf veins of P. hederaceum. And significant other features that cannot be found in the scientific description of P. hederaceum. But Philodendron hederaceum does have many variations and is the source of great confusion by collectors. Collectors prefer to call it Philodendron scandens, Philodendron micans, Philodendron miduhoi or one of many other names. But those names are only synonyms of the species Philodendron hederaceum! Collectors just refuse to accept that fact and continue to apply their own conceptions as to which is P. scandens or P. micans or even Philodendron 'Brasil'. But they refuse to call it Philodendron hederaceum as if the name was a disease. Collectors tend to believe if it is to be a "micans" it must have velvet leaves with a distinct heart shaped leaf blade and remain small. Do you know in a rain forest that plant can grow to 48cm (19 inches)? Do you know it can loose that velvet sheen? Do you know the shape of the leaf blade can change? Well, that is the world of natural variation within a species! The discussion among botanical scientists about variation goes back at least 180 years. It is a very old discussion that is still argued mostly by plant collectors today. Collectors just don't like the idea of variation. P. hederaceum always has that scandent (close climbing) habit, short petioles, long internodes, deciduous cataphylls which fall from the plant and a solitary inflorescence with normally green spathes that are reddish to purplish on the inside. A cataphyll is the sheath that covers around a newly developing leaf blade. And in nature it does not enjoy low light, the exact way collectors always want to grow it and often grows in bright light. Within a large number of aroid species as well as other plant genera there is near constant change. Part is during the life of a single plant and is the ontogeny of the plant or changes observed as that plant grows. Think of it as a child. Children grow all the time and constantly change in appearance. If you just look at your own child you are looking at that change. We often call the changes that occur during the life of a plant morphogenesis (the changes seen as it grows from juvenile to adult). Morphogenesis is the same as ontogeny. But the other change, or natural variation within a single species, is not sudden. It occurs over a very long term which can easily be eons. And that long term variation has created a great deal of confusion and controversy among collectors regarding species. Confusing? Perhaps I can help you to understand the dilemma of natural variation brought upon botanical scientists all by themselves. A dilemma which plant collectors continue to fuss about today.