pbs Digest, Vol 30, Issue 7

bonaventure@optonline.net bonaventure@optonline.net
Thu, 07 Jul 2005 21:27:59 PDT
Judy, all I can think of is that the hood of the spathe acts sort of as a "trap" for the pollenator. It presents translucent surfaces so that perhaps the insect flying up to the light hits the inside of the spathe and falls back in. These glowing windows or stripes can really be seen well in a backlit bloom of Arisaema costatum, giving a "stained-glass window" effect.
Perhaps the emerging bloom senses brighter light coming from the path and turns the back of the spathe, the whole bloom therefore, towards the brighter area and away from the human veiwer. 
Or it could just be perverse spite...

Bonaventure Magrys
in muggy superhumid central New Jersey

> Message: 14
> Date: Thu, 07 Jul 2005 09:47:07 -0400
> From: Judy Glattstein <jglatt@ptd.net>
> Subject: [pbs] orientation
> To: pbs@lists.ibiblio.org
> Message-ID: <42CD325B.6090809@ptd.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> I have two Arisaema fargesii flowering with their "backs" turned 
> to the 
> path they are near. Arisaema respond well to digging while in 
> flower, so 
> I could lift, turn 180 degrees, and pop them back into the same 
> location. Or, I could try moving them across the path.
> This is something that has occasionally intrigued me: do arisaema 
> present the same orientation from year to year? In other words, if 
> I 
> spin them 180 degrees will they flower as I wish next year, or 
> will they 
> stubbornly refuse to display their funny faces. What determines 
> why 
> their flowers face the way that they do? With tulips I know that 
> the 
> first leaf appears on the stem on the flatter side of the bulb. 
> But that 
> has nothing to do with the flower.
> Any observations, comments, suggestions?
> Judy in summertime New Jersey. Gray and rainy today, which means 
> it may 
> not reach steam bath conditions as it often does when the sun shines.

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