Re: secondary hemiepiphytes

From: "Jay Vannini" interbnk at infovia.com.gt> on 2000.05.24 at 02:21:42(4621) Dear Marilyn: Depends on the species in my opinion. Selenicereus (formerly Deamia) testudo is commonly observed to start life either as an epiphyte or as a seedling that snakes up (in this area) palms and tropical oaks. Either way, it is unusual to see them "tapped" into the ground as a mature plant. These cacti, in addition to some members of the other genera I mentioned appear to "trap" debris with their stems and roots and are quite successful after having "lost" their original soil root system. I have a Cuban species, S. cf. inermis that has long since overflowed out of its basket and many meters up into a tree where some stems have broken, re-rooted and continued on their way. I emphasize that this is under "wild" conditions - I am not certain that either a Monstera or a Selenicereus can duplicate this feat on a well-scrubbed brick wall! On the Vanilla query by B. Magrys: Vanilla is a fairly large genus with a pantropical distribution. While V. planifolia and V. pompona (valid?) are widely cultivated on trellises after growing up from the soil, there are, as I understand it, a number of smaller spp. that are purely epiphytic in habit. Does Vanilla planifolia commonly leave its soil root system? Frankly, I don't know the answer to this. Kind regards, Jay +More -----Original Message----- To: Multiple recipients of list AROID-L Date: Martes, 23 de Mayo de 2000 03:26 p.m. Subject: Re: secondary hemiepiphytes >As a gardener who knows little about the mechanics of plants, I recently >removed the pot under a Selenicereus which had parted company with its base >and root system [due to rot] in the pot and was happily growing up a cement >wall 30cm. from the ground. Do I understand fom your discussions, that this >plant will now keep on growing as it is, attached to the wall, and get >nourishment from the air. >Marilyn van den Bergh. > > >----- Original Message ----- >From: Bonaventure W Magrys >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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