Re: Nepenthes pitcher fluid

From: David Evans (
Date: Thu Nov 18 1999 - 22:22:33 PST

Date: Fri, 19 Nov 1999 01:22:33 -0500 (EST)
From: David Evans <>
Message-Id: <aabcdefg3936$foo@default>
Subject: Re: Nepenthes pitcher fluid

Dear Joachim,

On Mon, 1 Nov 1999, Joachim Danz wrote:

> while watching the growing cycle of my Nepenthes plants I was
> surprised how long the pitchers of some species last after they begun
> to wilt. It seems to me that the wilting process can stop for a
> prolonged period of time after about the upper third of the pitcher
> has wilted. At nearly all pitchers the lid turns away from it's
> normal position when wilted and then can't protect the pitcher-fluid
> from rainwater any more. So now my question is will the plant benefit
> from this additional liquid?

     I don't know why more people don't realize, but most Nepenthes
(except for N. mirablis, it doesn't seem to hold it's old pitchers) use
their older pitchers to collect water. N.ampullaria is rather like
S.purpurea, the pitchers are open to collect rain all the time. Also, I
have noticed the pitchers on N.ampullaria don't died back half way because
this wouldn't let it use it's funnel shaped peristome to take in water,
while protecting the food already in the pitcher. I add water to half
dead pitchers all the time and most of the time this water is used by the
plants. Some species are more adapted to this than others. Also, lower
pitchers are more often used, but even the upper pitchers of N.lowii are
openned to rain and cleverly designed so that excess rain tilts the
pitcher and poors out without washing away trapped food.
     I believe this is a very misunderstood need that has had profound
effects on the evolution of these pitcher plants. Ever wonder why
N.ampullaria almost never makes upper pitchers? Probably because it can't
get away from using them to collect rain. If it did have upper pitchers,
they would fill w/ water and pull the plant down into the shade. I
figure this why it is so good at producing basal rosettes, they are
supported by the ground--regardless of their size and the weight of water.
Why are the lids of N.veitchii so quick to brown and shrivel? Probably
because it is adapted to clasping onto tree trunks where it's huge
pitchers have plenty of support and it doesn't really need much of a lid
to protect it from the excess weight rain brings.

Dave Evans

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