I wanted to make sure you got a good answer to your question so I shot off a quick note to Dr. Wilbert Hetterscheid who is the world's leading botanist in the field of Amorphophallus species. This is Wilbert's response:

"The tuber is indeed the (strongly condensed, undergound) stem, consisting in most species of only one node, being renewed very year (few exceptions exist). The leaf is developing from the stem. I wouldn't call the leafstalk a "trunk" because that indicates something like the "stem of a tree. It is a leaf stalk and that is the best indication (botanists call it a
petiole). The rest of the leaf is the blade or "lamina" cut up in several"leaflets" but none of these latter are real leaves, they just imitate it as part of a full scale tree-imitation.

In many species (most) only one leaf develops per season (except often in seedlings which stay in growth a bit longer and develop more leaves). Some species produce more than one leaf when mature (paeoniifolius does often, few do it always and a few are semi-evergreen).

Drooping leaf margins might be dormancy setting in but may equaly be a sign of a tuber not being healthy, maybe losing roots. The normal procedure of starting dormancy is a furrow developing along the leaf stalk and yellowing of the leaflets. Drooping is the next and then the leaf stalk suddenly collapses."

You were doing a great job of describing your plant but I saw one error I thought you'd like to understand better.

The plant has one single leaf thus only one petiole rather than five. The petiole is the portion of the leaf that is the support for that blade. I failed to ask Wilbert if the 5 leaflet supports you were trying to describe as "petioles" are truly midribs but I suspect that would have been his response.

Most people try to call the leaf support a "stem" but the stem is the central axis of the plant which produces nodes. Nodes produce roots and petioles. The petioles are part of a leaf and are the "stalks" that support the leaf. In the case of this genus the stem is underground and is known as the tuber.

Great question and I hope this helps.

Here is a link that might be useful: What is a stem? What is a petiole?

Since Dr. Hetterscheid is from the Netherlands his thoughts may not translate precisely to English in the same manner we might have phrased the statements. I didn't want to edit Wilbert's information and quoted it exactly.

Please keep in mind our native language is not his native language but I'm sure you will understand his thought process.

WOW! thanks exotic. No other signs that would indicate dormancy or being unhealthy just the drooping. I was under the impression that if properly taken care of dormancy would only occur every 18-36. Mine just awoke 5-6 months ago.

As a result of Wilbert's second comment as to the possible cause of the leaf drooping be sure and check for impending dormany as he recommended. If you don't see those signs I would take off as much soil as possible without digging up the tuber and check it to be sure there is no sign of any decay or fungus. I lost two a year ago by making a bad assumption while another stayed up showing no signs of distress.

If it appears healthy then leave it potted but if you see any rotting then you'll have to dig it out to treat it.

Lots of growers cover the tuber with Cinnamon which is a great fungicide but in that case you'll have to keep it out of the soil until it scabs over. Yep, it will go dormant for sure then but thats better than loosing the plant.

Although there are "norms" for dormancy there just aren't any set rules. I've had mine come up and then go dormant six months later only to regrow five months after that. Growers like to have set patterns to follow but Mother Natures just does it the way she pleases. I know good growers that dig them up as soon as they go dormant just to be certain there is no damage to the tuber.

I was curious if the supports for the leaflets were known as midribs as they are on many aroid leaves. I sent another note to Wilbert and this is the answer, "It is often called the rachis, and then there may be rachids of lower and higher order depending of the number of times they branch."

Thanks for posting this. I learned something new as well!

Exotic..I cannot thank you enough. So...I scrape off the soil to expose the corm..what am I looking for as far as fungus? then If I am understanding you correctly..I remove it from the soil and cover the corm (that's the bulb right?) with cinnamon. Could I remove all soil and plant it in something like vermaculite until spring?.

The fungus will present itself as a soft spot on the surface of the tuber (corm, stem, bulb). The chances are if it is there you'll see it near the top but you might gently run your finger around the tuber just to be sure.

Try not to disturb the roots or it will go dormant for sure. If you find any soft spots take it out of the soil and sprinkle the cinnamon all over the tuber. At that point you'll have to leave it out of the soil to allow the cinnamon to work. Most just wrap it in slightly damp burlap but the vermiculite should work, just don't start watering it. There is a link on the International Aroid Society website to the Berlin Botanical Garden. They offer lots of good advice. Once their plants go into dormancy they don't water at all until it comes back to life. I know the curator of the Missouri Botanical Garden and she does the same thing.

At the International Aroid Society show in Miami last month I talked to several growers that follow this exact growing method. I've been using it for over a year with great results. There is some disease control info on the page as well.

Be sure and read how they pot and water their plants.

Here is a link that might be useful: Berlin Botanical Garden