Amorphophallus impressus tries to impress us
Since I noticed the inflorescence developing last week, I have been keeping a close eye on this Amorphophallus, as the label on its tag have already faded, and have been wondering what it could be. However, I also noticed two nubs on the left side of the inflorescence. Hmmm... The thing with Asian species is that after blooming, the tuber stays dormant for the rest of the year, to reappear only on the next growing season, which would be next year. But obviously this one isn't going to stay dormant after blooming, so it must not be an Asian species.
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| Inflorescences or leaf growths? We'll know soon enough. |
Nevertheless, the spathe structure reminded me of A. lewallei, from western Burundi. But the spadix is much taller, in proportion. I began scouring my head for similar African species, then thought about A. henryi, then A. impressus. To settle things quickly, I asked Alan Galloway, who probably has the largest and most diverse collection of plants from this genus in the world, about his opinion. His reply was quick: Amorphophallus impressus, which is a species found on Malawi in southeastern Africa. Great! Except for one thing: I do not know nor remember how I got it. But as it turned out, I have been keeping this plant for at least three years now, as 'Amorphophallus indet.' That means that even if I can still read the writings on the tag, I still would not be able to pin it down to species. I have a couple of photographs of the plant from June 2015, shown below:
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| Sunshine on my shoulders. |
When I visited it again by 3 PM, the spathe has noticeably reflexed much further. By this time the stench had intensified, although still rather weak. The odor reached its peak by around 4:30 PM though it is detectable only if you come close or there is a fair amount of breeze blowing. Combine the rabid stench with the spathe behavior and it is evident at this stage that the structure has opened itself up fully for business.
Contrary to what many people think, that entire structure is NOT the flower. The flowers are tiny and much simplified, and positioned below the appendix; immediately below it are the male flowers, and beneath it is the female zone. The flowers and the appendix are all in a single organ called the spadix. The female flowers are receptive only prior to the shedding of the male flowers' pollen, so self-pollination is just not possible- except perhaps for A. muelleri, which is said to be apomictic. To get seeds, you are going to need two specimens, with one that is blooming a bit ahead to the other one, although more advanced collectors can store pollen for latter use.
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| The male floral zone. Notice the droplets of nectar (?) on the appendix surface. |
By nighttime the spathe began to roll up. This photo was taken at about 10:20 PM. The stench was still there, only weaker, but by this time it had become mixed with a discernible musty odor.
On the second day and on the same night it rained heavily, and that is when I realized something: the spathe apex that has appressed itself on the spadix probably serves the purpose of shielding the urn, or the floral chamber, from downpours. After a particularly hard rain I took a peek inside, and just as I anticipated, it was perfectly dry all around the floral zones. Nifty plant, don't you think?
This habit of the spathe rolling towards the spadix is not new. Some species do it, including this one I collected (with the benefit of a collecting permit) from a remote, little explored area in northern Luzon.
Anyway, it is also on the second day that the male flowers started shedding its pollen:
The oblique orientation of the urn is clearly apparent on the photo below. The floral chamber is much constricted towards the base of the flaring portions of the spathe, similar to a few other African species. I reckon that this 'diaphragm' prevents trapped insects from ever leaving their obnoxious prison.
Actually, that wasn't a far-fetched idea because on the morning that the spathe unfurled (June 5), I noticed a lone trap-jawed ant (genus Odontomachus) inside the chamber, totally unable to escape as the diaphragm rims served to function as an effective barrier.
Here's a bad and blurry photo of the ant inside the chamber:
And here is the inflorescence as seen from its rear, showing how tightly appressed the spathe apex is to the appendix:
In this configuration, the floral chamber is well-protected from rains:
And yet, the floral chamber can still be accessed by visiting insects through a gap on both sides:
On the third day, the spathe coloration has noticeably faded, compared to how it was on the first day.
The species name impressus is Latin and translates to 'printed', although it isn't clear to me what is being described as such on this species.
But what is even more puzzling is that I can't still figure out where or to whom I got this plant from...
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