I am not a botanist. But I have been a student of aroid botany for close to 20 years. During the years I've set out to learn about aroids I've been fortunate to meet and engage the minds of some of the world's top aroid botanists. Top of the list in the category of the "world's best" would include Dr. Tom Croat of the Missouri Botanical Garden, Dr. Eduardo Gonçalves from Brazil, and Pete Boyce from Singapore. Because I'm curious, I exchange emails with these experts almost weekly. So why is that of importance? Recently on this board there was a discussion concerning a couple of aroids which were very difficult to identify from the photographs. That is not unusual. I sometimes read where collectors of tropical species offer immediate identifications for species on numerous garden boards within the large group of plants known to science as Araceae. That can be dangerous, and often wrong. Commonly, aroids include the genera Philodendron, Anthurium, Monstera, Alocasia, Epipremnum, Scindapsis, Rhaphidophora,Colocasia, Dieffenbachia, Caladium, Xanthosoma, Amorphophallus and quite a few other smaller genera, some extremely rare, such as Rafflesia. Unfortunately, identifying an aroid, especially in the juvenile state can be extremely difficult. And almost any plant grown by "house plant" growers is a juvenile. People expect all plants of the same species to look alike. In aroids they frequently do not. When first developing the leaves, most normally have "heart shaped" leaves. But as they grow they change dramatically. They morph. And many species are variable. Variableness simply means the species can have very different leaves in either the juvenile and/or adult stages. Plants within the same species, such as Philodendron hederaceum have as many as twenty scientific names! You probably know them as Philodendron scandens, Philodendron oxypetalum or one of many other names. But to a scientist, they are P. hederaceum. The species is extremely variable! So much so, they have fooled botanists for over 150 years! As a result, many species (Philodendron, Monstera, Epipremnum, and others) look almost identical in the juvenile form. But since they come from different regions of the world they often need different care. Some need more, or less, water. Some, more or less light. Many prefer damp rain forest conditions and still others prefer arid growing conditions with only occasional water. So a snap opinion on the "species" name can end up in the collector loosing the specimen. Most collectors know that adult leaves within the genera Monstera have holes in their leaves. But within the genus Monstera the leaves do not develop the holes until they begin to reach maturity. But on the way to adulthood the leaf can look just like a Philodendron. But even then, they continue to change shape as they grow. As a result, instantly attempting to declare a juvenile a "pothos" may be totally wrong. And often is. A plant commonly sold as Philodendron Silver Queen is actually a Monstera sp. As a result, it is quite unwise to immediately offer an opinion when some plant is in the genus or group Philodendron, or Epipremnum (pothos), or any other genus when the plant is young. Recently, on another board, one individual was apparently upset that Dr. Croat, who is recognized at one of the world's leading experts in this group of plants, could not immediately identify a species from a single photo of a juvenile leaf. My friend, aroid expert Julius Boos, explained all of the processes involved in aroid identification much better than I could ever do so. As a result, I am including his response with permission. Julius is well known in the aroid community and has written many scientific papers and has assisted in the identification of several species writing their scientific descriptions for scientific publication. Please take the time to read, and absorb, what Julius explains. For those not familiar with aroids, a spathe and spadix are the inflorescence (often called a flower) produced by the species in order to reproduce. In the case of aroids, they are quite significant to a positive identification. Julius wrote, "Please allow me a moment to attempt to explain how a taxonomist may ID any specimen sent to him. In most cases, the plant specimen, or better yet a series of specimens (or in rare cases a series of good photos) which show an adult plant and infloresence showing a close-up of the spadix at male anthesis. The photos should be of a mature plant and have several leaves in which the examiner can look closely at both sides of the leaf blade, the petiole, the rhizome, etc. The specimens must have good collecting data attached. The genera in which you are interested are almost impossible to ID to genus, far less to a species in a juvenile stage of growth especially without collection data. In the case of Anthurium, unless you can supply collection data it may be impossible to ID a specimen even with an inflorescence. This genus occurs widely, from Mexico, through Central America and the West Indies and down throughout South America to Uruguay. There are over 800 species, many undescribed, plus there are many 'man-made' hybrids in cultivation. So, without critical collection data it is impossible for even "the" expert on the genus Anthurium, who just happens to be Dr. Tom Croat, to give anything more then a qualified guess based on just a photo. My advice to you is to obtain collection data from any collections you may visit, as without this the plants you see, or even get cuttings of, can not be identified with any accuracy even to genus, since all juvenile vine-like aroids look very much alike. Take photos of their adult leaves, their petioles (their length, amount/length of the sheath, shape in cross section, their rhizomes, etc.), and then grow them till they bloom. Cut a portion of the spathe away and photograph the details of the sexual parts. With the above information Dr. Thomas Croat and Mr. Pete Boyce, who happen to be two of the world experts on most Aroid genera, may be able to give you an accurate identification of any aroid. But collection data is necessary, otherwise an ID by anyone is just an educated guess. Since almost no request for identification of an aroid on this board includes photos of the adult leaf, the collection data detailing where the species originated in nature, and does not include photos of the petiole, the spathe and spadix including cut-away photographs, and other important features, it is next to impossible for anyone to be "certain" or "guarantee" or be "positive" of a species identification. Some who have studied aroids for years may be able to offer a good guess, but it is still just a guess." Am I suggesting everyone put up 10 photos of any single plant? Certainly not! Am I suggesting no one should attempt to make an identification? Again, certainly not. But more detailed information and good photos would be helpful before offering an opinion. So why is that important? Within the rain forest, an estimated 70 to 90% of species live up in the canopy. They do not normally live on or near the ground. Some come from wet rain forests, some come from the fringes of rain forests and some come from drier climates. Without knowing what the species actually may be it simply is not possible to give accurate advice on how to care for the species. Especially when many species are epiphytes and live attached to the side of a tree and not growing in soil! (Although many will survive in soil.) So the next time you are tempted to give an instantaneous "positive" identification to a plant that is from a genera belonging to the aroid group, think about what you just read Julius explain. Some may be able to come close, but no one can be absolutely certain unless they are on a par with professionals like Dr. Croat, and the others who are his peers. Personally, I make no claim be being among his peers! And Dr. Croat will be very quick to tell you he often cannot identify a juvenile from a single photo. Claiming anything that looks like a "pothos" is actually a "pothos" is likely to be incorrect. Does that mean you should not offer an "opinion"? Certainly not! Just remain open minded. Unless you are trained to recognize small details in aroid species, the identification is highly likely to be flawed. **My comment about Rafflesia being an aroid is incorrect. Both Julius and Michael F quickly pointed that out! I left it in so you'd understand the comments below. But please do not be confused as I was, Rafflesia is not in this group pf plants.
Thanks for this post photopro, I corrected the title (only admin has access to Titles.) Interesting info, especially considering how commonly grown aroids are as house plants. (PS: Should that be Rafflesia?)
Likely spelled wrong! My system doesn't catch all the scientific names. Wish it did! I'll go fix it now! I hope this helps a few growers out.
Is Rafflesia in the Araceae now? I've always seen it cited in its own family Rafflesiaceae, but I guess it could have been lumped in. I know Lemnaceae (duckweed 'family') was merged into Araceae recently. Why not lump them all into one (well, a number rather less than 800!) species? ;-) I know of some very influential botanists who take this view in some other plant groups – if two herbarium specimens from different areas and labelled different species are indistinguishable in all characters, they make the one a synonym of the other. In some cases I'm thinking of, they definitely go too far in this and synonymise good taxa (look up e.g. Pinus remota in Flora N America), but in other cases, with good justification.
In the case of Rafflesia, articles I've seen in the aroid community list it in the aroid group. But it is extremely rare and rarely seen unless it produces an inflorescence. That inflorescence can weigh more than 20 pounds and is now considered (by some) the world's largest "flower". But as soon as the inflorescence dies, the plant vanishes back into the host vine leaving little if any trace. It has no stem, no leaves and leaves little trace in the jungle. Within the genus Anthurium, there are now approximately 800 known species. But the big problem is this group of plants is highly prone to voluntarily hybridization in the wild. If another similar species is nearby, and the right insect brings over the pollen, a hybrid can easily be produced. Since birds and animals carry away the seed berries they end up growing in the same jungle and often "appear" to be a new species. Only by examination of the spathe and spadix can a qualified botanist tell if it is in fact a "new" species or simply a natural hybrid. Botanists do however divide Anthurium species into sections. As an example, Anthurium regale, Anthurium crystallinum, Anthurium magnificum and A warocqueanum are in the section Cardiolonchium. This group is characterized by plants with leaf blades that appear velvety on the upper surface. The same is true with Philodendron species. There are numerous sections based on growth form and blade shape. Whether we agree or disagree with these classifications is irrelevant. Since I'm not a botanist I have no input. I just read this stuff and do my best to digest, understand and be capable of explaining it to others in common language. But since folks like Dr. Croat, Dr. Simon Mayo of the Royal Botanic Garden Kew in London, Dr. Gonçalves, Pete Boyce and others have spent their lives studying these specimens I simply trust them. I sometimes question them, but I don't push it!
In regard to this quote, by Michael F, "Is Rafflesia in the Araceae now? I've always seen it cited in its own family Rafflesiaceae, but I guess it could have been lumped in. I know Lemnaceae (duckweed 'family') was merged into Araceae recently." I just checked TROPICOS and the Rafflesia group are not lited as Araceae. I went to several aroid posts which include discussions of thess odd plants and it is unclear whether or not they intended to imply Rafflesia is an aroid. They may have been simply discussing the common traits of stinking like dead meat common to some (not all) of the more notorious aroids such as Amorphophallus titanum. But they certainly left the impression it is an aroid. I'm going to dig into this one now!
Just had a look on the APG website, they put Rafflesia in the Malpighiales (same order as willows, etc). So not an aroid! Must have just been talk about flower sizes, not botanical relationships. http://www.mobot.org/MOBOT/Research/APweb/orders/malpighialesweb.htm#Malpighiales
Everything I've read this afternoon indicates you are correct. One thing that really threw this off balance is one source offers a link to the International Aroid Society as a reference during the discussion! But I checked the IAS site and there is absolutely nothing there about this species! My error! See, I told you I was just a student of botany.
These things happen! Instinct keeps telling me to spell Malpighiales as "Malphigiales" . . . every time I have to remind myself that's not how to spell it :-)
Appears the more we try to learn about plants, the more we find we don't know and need to learn. I've already been a "student" of aroids twenty years! Somehow I don't think I'll be earning a diploma anytime soon!
