----- Original Message -----
To: Multiple recipients of list AROID-L
Sent: Tuesday, May 23, 2000 8:21 AM
Subject: Re: secondary hemiepiphytes
> Jay,
> What about Vanilla vines?
> Bonaventure Magrys
>
> "Jay Vannini" on 05/20/2000 11:15:57 AM
> Please respond to aroid-l@mobot.org
>
>
>
> To: Multiple recipients of list AROID-L
> cc: (bcc: Bonaventure W Magrys/ADM/SHU)
>
> Subject: Re: secondary hemiepiphytes
>
>
>
>
> Alan:
>
> As a lay observer, I don't pretend to have an answer to your question, but
> rather will pose another related one - that is - do these "hemiepiphytic"
> aroids always dispense with soil root systems once airborne elsewhere in
the
> Neotropics?
>
> Sorry to jump in so late here with my two centavos worth, but it is my
> observation that several of the large scandent aroids that are native to
> northern Central America commonly continue with very visible links to the
> ground, even as they pursue the good life in the upper canopy. I have
> recently examined a vigorous wild population of the species that you first
> mentioned (Monstera deliciosa) in premontane wet forest near that Chiapan
> border and, offhand, I remember that many of the plants I saw could be
> traced back down to the ground down very robust host-clasping stems. This
> was also evident in mature Monstera friedrichsthalii, Syngonium
steyermarki
> (ID?) and a very large Philodendron sp. seen in the same region.
>
> Again, this is only my opinion from admittedly casual observation, but it
> seems to me that while these plants CAN readily dispense with ties to the
> soil, they don't necessarily have to do so. Therefore, this event seems
more
> an adaptation to accidental (?) loss of the original root system - clearly
> an advantage to plants whose fates would otherwise be tied to that of
their
> hosts following its death. As anyone who has visited an old light gap
caused
> by a tree fall in humid tropical forests in this region can attest, many
> mature vines attached to fallen trees have often just reverted back to the
> juvenile climbing stage and headed for the nearest handy trunk to
> re-colonize.
>
> Perhaps we shud refer to this regenerative phase as "phytopragmatism"
(just
> kidding).
>
> Amongst several other groups of plants that I am familiar with, there are
> indeed clear parallels to this habit in some aroids. Several of the larger
> "highland" Nepenthes pitcher plants from tropical Asia, most notably N.
> lowii and N. pilosa, often part from old, rotting basal stems and continue
> to grow and reproduce as epiphytic canopy vines. Likewise, many cereoid
> cacti inhabiting moist tropical habitats, esp. Selenicereus testudo,
> Hylocereus spp. and Werckleocereus spp. also do this on a regular basis.
> Again, this appears to be an adaptive response by succulent-stemmed
climbers
> to environments conducive to loss of basal stems and roots due to fungal,
> bacterial and insect attack over the relatively long life of the plant.
>
> Your questions do open an interesting avenue of research, that is, how
> common is this ability in tropical climbers and what species do
> "voluntarily" cut ties to the ground, and why. There are a number of
> individuals that attend this forum that are familiar with regions with far
> higher epiphyte diversity than Guatemala and Mexico; perhaps they will
share
> their views on this subject.
>
>
> Best of luck with your project,
>
> Jay Vannini
>
>
>
>
> ----- Original Message -----
> From: "alan san juan"
> To: "Multiple recipients of list AROID-L"
> Sent: Friday, May 19, 2000 10:26 PM
> Subject: Re: secondary hemiepiphytes
>
>
> > ok, cool. Thanks to those who gave answers.
> >
> > I note though that most explanations focus on why a plant would want to
> > get to the canopy area, as opposed to why it would elect to GET RID of
> > the underlying stem. One writer, who wrote by email, noted that this may
> > be simply the result of cumulative damage to the lower (and older)
> > regions of the plant. Although this may be possible, my understanding is
> > that the degradation is too drastic to be simply due to random
> > accidental events, and it of course does not address why this would
> > occur in several diffrent groupings of plants while not in most others.
> > Indeed, I once observed a large PHilodendron in a greenhouse which clung
> > only 1.5 meters or so above the ground...its old pot lay forlornly below
> > it....
> >
> > Another notes that adventitious roots could make up for the loss of a
> > stable water supply, but then notes that conditions even in rainforst
> > areas up in the canopy is relatively different from one time to another
> > and from even one tree area to another. Many plants (I think) do not
> > dispense with their ground roots, while these MOnsteras and
> > PHilodendrons do....
> >
> > What characteristics do these plants and similar others have that differ
> > from other vinelike plants that start at ground level but never
> > relinquish their hold on earth? Is this a competitive advantage that
> > allows these plants to compete equally against others in similar niche
> > (well, you may have a stable water supply, but you gotta spend energy
> > maintaining it, whereas ther is a chance I may end up in an inhospitable
> > spot, but in the meantime, I can recycle old tissue matter into growing
> > at the tips, and growing faster than you)...
> >
> >
> > anyways, thanks for the answers.
> > alan in New Jersey, USA
> >
> >
> >
> >
>
>
>
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