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The Exotic Rainforest
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In depth information on how to grow Philodendron species, Click this Link

Within our collection we have many species of Philodendron.  If you are seeking other photos, click this link:

Philodendron holtonianum

Philodendron holtonianum, Photo Copyright 2008, Steve Lucas,

Temporarily known as
Philodendron holtonianum
Possibly an unnamed species
Not Philodendron tripartitum

Philodendron holtonianum, Photo Coprygith 2008, Steve Lucas, www.ExoticRainforest.comWhen I first began to research this plant I thought the specimen was likely a growth form of Philodendron tripartitum since the name being used, Philodendron holtonianum, is a synonym of that species.  The plant didn't look like any known variation of P. tripartitum but aroid botanist Dr. Tom Croat of the Missouri Botanical Garden in St. Louis says in one of his journals P. tripartitum is highly variable taking on a number of different shapes throughout its range.  As I would soon find out this specimen may actually be totally new to science!  As a result, Dr. Croat has suggested using an informal form of the name until a final species determination can be made.  This link better explains natural variation which is a known scientific subject: Click here.
I asked Dr. Croat about the species and sent him a photograph.  In a personal email he replied:  "This is not Philodendron tripartitum but rather a species from eastern Ecuador.  I am calling it P. holtonianum but it may in fact be an undescribed species."  Although this specimen, which Dr. Croat is currently calling Philodendron holtonianum, has the 3 lobes common to P. tripartitum Dr. Croat's personal message indicates this is not one of the species' variations.  The Philodendron is very thinly coriaceous which means it's leaf blades feel like very thin leather.  If you look closely you'll notice the leaves emerge as a single long slender blade.  After some growth they begin to develop the "ears" (lobes) of a tri-bladed specimen.  The lobes progressively become larger as the plant matures. In early November, 2008 Croat elaborated, "The reason why I doubt that it is really P. holtonianum is that that species is from the western slopes of the western cordillera. Of course the curious thing is that it really does look a lot like the type so I need to study the situation further."
Our specimen is a climber and is already dropping long "air" roots into the soil.  As can be seen from the photo by Enid Offolter of Natural Selections Exotics in Fort Lauderdale, FL   the blade changes substantially as it matures.  Enid had these comments about the growth of Philodendron holtonianum, "The large leaf is probably 8 or so feet up the tree now.  The leaves started to widen and change when it was only 3 ft or so off the ground.  In recent years I have been amazed at how much Philodendron and Anthurium leaves will change if allowed to climb and reach maturity.  Even very old plants, if not given some sort of totem, will scramble around with immature leaves.  When very young, the leaves on holtonianum are very narrow and are often a single strap."  At this point little published work is available about the plant.  One thing is known for certain: it is rare.  Since the plant has proven to be an epiphytic climber we have elected to plant it in very well draining soil and give it a totem just as Enid suggested. 
Philodendron holtonianum, Photo Coprygith 2008, Steve Lucas, www.ExoticRainforest.comWe prefer to use an equal mixture of good potting soil, peat moss, orchid potting mix, and Perlite.  Since this plant is a rainforest species from the Amazon region of eastern Ecuador, if grown outdoors it should be watered often during the hot portions of the year, less frequently in winter.  We are growing it in moderately bright filtered light.  The largest leaf on our specimen, which is obviously not mature, is now 13 inches (33cm) in length and 8 inches wide (20cm) at the widest point of the lobes.  I'm told the leaf blades can get as large as 2 feet (60cm ) long by 18 inches (46cm) wide.  For now we are just watching it grow to see what can be learned.  The name Philodendron holtonianum is used in non-italics since this specific plant is not yet published.  The name is being used temporarily until a scientific determination is finalized.  
Philodendron species, and especially hybrid forms, are known to be highly variable and not every leaf of every specimen will always appear the same.  This link explains in greater detail the scientific principle of natural variation and morphogenesis.  Click here.

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