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BACPS | Newsletter |
| Spring 2005 |
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BACPS Members in the News |
| Summer at Filoli | |
| May Meeting Minutes | |
| Evolution of the Utricularia Bladder Trap: A Short Summary | |
| Bathtub flava | |
| Potting Pings | |
| Ultimate Accessory | |
| Upcoming Events |
Last month's San Mateo Times article about carnivorous plants, featuring Peter D'Amato, Stephen Davis, and Judith Finn:
http://www.insidebayarea.com/portlet/article/html/fragments/print_article.jsp?article=2800021
This week's San Francisco Chronicle article about Bill Weaver's flowering Amorphophallus titanum:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/07/12/BAGUDDMB7M1.DTL
Stephen Davis's pond and bog are among those featured on the Santa Clara Valley Koi and Water Garden Club's pond tour this Saturday, July 16:
by Stephen Davis
Many thanks to Arthur Yin for stepping up at the last minute and spending a day educating so many people about carnivorous plants at the Filoli summer BBQ. He met quite a few interesting people, and the staff at Filoli fawned over him and the plants. It turns out that one of the gardeners there is a CP fan, and they even have some Nepenthes hidden away in a greenhouse!
Filoli was very appreciative of our participation, and we will almost certainly be invited back next year.
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by Judith Finn
Bay Area Carnivorous Plant Society Meeting
May 1, 2005
Location: University of California Botanical Garden at Berkeley
Attendance: 40 people
Joe Mazrimas brought in Utricularia quelchii, U. asplundii, and a unique crested form of Sarracenia leucophylla, 'Tarnok'. Utricularia quelchii is from the highland tropics of the tepuis of Venezuela. He uses sphagnum and perlite and then top dresses with live sphagnum.
Bill Weaver displayed Drosera filiformis, D. dichotoma 'Giant', and D. binata. He told us that he waters them twice a day and severely prunes them once a year.
Tony Gridley exhibited a lavender-flowered Utricularia tridentata and a white-flowered U. nephrophylla.
Larry Logoteta brought in a Drosera regia that he grew from 15-year-old seed, some Sarracenia leucophylla hybrids, and S. jonesii.
Doris Quick showed us her red-flowering Drosera adelae. She gives them morning sun and covers them with a bell jar for humidity in warm weather.
Stephen Davis brought in a Drosera occidentalis ssp. occidentalis and D. occidentalis
ssp. australis. He grows nine species of Drosera on his windowsill.
Dominic Diaz displayed a three-and-a-half-year-old Sarracenia hybrid of flava and leucophylla that he obtained from Phil Faulisi. It was brilliant red and gold. He potted the plant up in a mix of two parts peat and one part sand. To attain the intense color, he waters it with black tea or boils peat moss to make an acidic drink.
Lois Ochs brought in Utricularia reniformis. She started the seeds on New Zealand sphagnum and covers them with a plastic dome for humidity.
Melissa Mork brought in some carnivores to help beginners start a collection.
People brought in various Nepenthes, Nepenthes cuttings, Drosera, Darlingtonia, Pinguicula,
Utricularia, Sarracenia, and Venus Flytraps.
Stephen Davis asked for donations to help the U.C. Botanical Garden complete their fundraising for a new cage in the Fern/Carnivorous house, the custom-made glass sliding panels being the most expensive feature. The club has a $1,400 fund that it has been keeping for the project, and David Grey gave a generous donation, but the Garden is still short.
Cindy Slezak reminded everybody to sign up for the International Carnivorous Plant Society for $25 a year. Their journal, Carnivorous Plant Newsletter, is a wonderfully informative publication.
Stephen reminded us that we have the Annual Carnivorous Plant Show coming up September 11 at the Lakside Park Garden Center at Lake Merritt in Oakland. He needs volunteers to help with registration, display, publicity, etc. Please join us in making this a great show.
It is also not too soon to start thinking about volunteering to run for office at the Fall Meeting.
If we all do a small part, our society will remain vibrant and improve its usefulness to carnivorous plant lovers.
Christina Palmer asked for help and suggestions to make her team propagation project work. This is a really good idea to make desirable plants available for our collections.
Nicholas Matzke of the National Center for Science Education gave us a lecture on his ideas of how the complex traps of Utricularia developed (see his summary article below). There are no fossil records that show a clear path of development. He began by describing the battle between evolution based on Darwin and advocates for intelligent design. He gave the example of a mousetrap -- an object requiring multiple parts to function -- as an example of "irreducible complexity." This is a main component of the "Intelligent Design" reasoning. A Utricularia trap is also an example of a complex object requiring multiple parts. Does this make it an example supporting "Intelligent Design?" Mr. Matzke weaves his evolutionary hypothesis starting from the sticky passive plants that have some slow motion such as Pinguicula and Drosera to Sarracenia psittacina and juvenile Darlingtonia that are amphibious. Theories of amphibious pitchers developing vacuums, and pitchers evolving into lobster pot traps were also proposed.
by Nicholas Matzke
The intricate bladder trap of Utricularia has been compared to a human-designed mechanical mousetrap, and its origin is a long-standing mystery. The difficulty has been in imagining a viable series of transitional trap forms leading up to the bladder trap. For 100 years after Darwin's book Insectivorous Plants, only the eccentric panbiogeographer Croizat treated the origin of carnivorous plants in any detail, attempting to derive all trap forms from a common ancestor at the base of angiosperms. Croizat's scheme was unworkable, and in the 1980's models were proposed for the independent origin of adhesive/snap traps and pitcher traps, but Utricularia remained wholly mysterious. Recent molecular studies show several independent origins of carnivory, but indicate that pitchers are usually derived from adhesive traps. Croizat's suggestion that the bladder trap is a miniaturized pitcher is combined with previous models and evidence to produce a unified model of trap evolution, in which the bladder trap is derived from a series of pitchers and finally a Pinguicula-like curled adhesive leaf. Supporting evidence and possible tests are discussed. Although detailed questions remain, the basic mystery of the origin of the Utricularia "mousetrap" has finally been solved within a gradualist Darwinian framework, making extraordinary alternatives unnecessary.
The table below shows a summary of my proposed unified model for the evolution of carnivorous plants. My basic argument is that by looking at all of the carnivorous plants together, and examining both convergence (the evolution of similar traps from different starting species, due to similar forces of natural selection) and phylogeny (the tree of relationships between modern species, determined by DNA sequence comparison), a plausible model for the origin of the complex and baffling Utricularia trap naturally presents itself.
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Table: Unified model for the evolution of carnivorous plant traps. Taxa enter the carnivorous syndrome at the stars. Species representing examples of various trap forms are shown. The hypothesized pathways between forms are shown by grey arrows in the background. Obviously, this is not intended as a phylogeny, rather the purpose is to show that the different lineages repeatedly converge independently on similar forms in similar situations, and that the likely pathways between these forms can therefore be reconstructed, even though no single taxon contains all forms (although the group including Drosophyllum, Drosera, Dionaea, Aldrovanda, and Nepenthes contains many of them). The asterisk (*) represents a hypothesized extinct group of pitcher plants in the Lentibulariaceae. It can be seen that in the context of the model, such a hypothesis is not extraordinary. |
Recent molecular phylogenies have shown that plants with carnivorous traps have arisen several times independently, and then diversified into different kinds of traps. The three major phylogenetic groups are:
A few other carnivorous plant species (Byblis, Cephalotus) are isolated and not closely related to other carnivorous plants. In each of the three major lineages of carnivorous plants, simple adhesive traps appear to be the most likely ancestral state. This reinforces several pre-molecular conclusions about the evolution of carnivorous plants: The gradual evolution of passive adhesive traps (e.g., Drosophyllum) into active adhesive traps (e.g., Drosera) and then into traps that close so rapidly that glue is unnecessary (Dionaea) and that even function underwater (the minute Aldrovanda trap) has been proposed many times, starting with Darwin, and has been supported by recent morphological and molecular phylogenetic studies. It has also been commonly suggested that pitcher plants evolved by curling up a leaf to form a crude pitcher. The only thing that the new molecular phylogenies add is the idea that this ancestral leaf was probably itself an simple adhesive-leaf trap. The plausibility of this transition is seen in carnivorous plant traps that are intermediate in some respects (see table).
Based on the phylogeny, it appears that Utricularia and Genlisea are sister groups, with Pinguicula more distantly related. This has been recognized for decades; the puzzle has always been to explain how a simple trap rather like that of Pinguicula could gradually evolve into the complex traps of Utricularia and Genlisea.
If we accept the idea that Nepenthes pitchers evolved from an adhesive leaf that was also the ancestor of plants like Drosophyllum, and we accept the idea that the Sarraceniaceae pitchers evolved from an adhesive leaf that was also the ancestor of Roridula, then it is reasonably to hypothesize that a Pinguicula-like leaf could evolve into a pitcher trap. If Nepenthes and Sarraceniaceae are any guide, this ancestral pitcher plant would diverge into species specialized on different trapping environments -- flying insects, crawling invertebrates, and sometimes even swimming invertebrates (representatives of each kind of trap are listed in the table).
Sarracenia psittacina, for example, is a "pitcher" plant that has given up the pitfall method of trapping, and instead lies horizontal on the ground, relying on a "lobster-pot" mechanism of inward-pointing hairs to trap prey. The species has even been observed to be amphibious, trapping while submerged underwater.
How does this help us understand the origin of the complex Utricularia trap? Well, the sister genus of Utricularia is Genlisea, which is commonly described as employing a lobster-pot mechanism. Some Genlisea traps point down into the soil or mud, but other Genlisea traps are more-or-less horizontal, laying just below the surface. It is a very small step to get from a ground-resting, amphibious lobster-pot trap like S. psittacina, to an amphibious lobster-pot trap just below the surface of the soil or mud, like Genlisea. In his 1942 book The Carnivorous Plants, Francis Lloyd's defining work on the topic for many years, Lloyd himself described the Genlisea trap as "the most complex of the pitfall type" (p. 7).
So, perhaps the common ancestor of Utricularia and Genlisea was basically a subsurface lobster-pot trap, itself descended from a pitcher plant in the Lentibulariaceae that resembled S. psittacina. The trap would be tube-shaped, but not have a long-necked entrance like Genlisea. A recent paper on the molecular biology and phylogeny of suction capability found that the common ancestor of Utricularia and Genlisea had suction capability, perhaps in order to decrease nutrient loss in a submerged environment. The lineage leading to Genlisea specialized on improving the lobster-pot mechanism, reducing nutrient loss further with a long neck; suction ability was later lost in some lineages of Genlisea (Jobson et al., 2004). The lineage leading to Utricularia developed the trap door initially for the same function, as an enhancement of the lobster-pot mechanism. Folding over the lip of the entrance to form a one-way door would reduce both prey escape and nutrient loss. However, once a door is added to a lobster-pot with suction capability, a suction trap has been produced, and with this sophisticated trap in place the massive radiation of Utricularia into hundreds of species could proceed. Some of these Utricularia species remained terrestrial and retained many lobster-pot features (see figures in Lloyd), but some would become fully aquatic, dispense with lobster-pot features, and rely entirely on their unique suction trap.
Is it extravagant to conjure up a whole extinct genus of pitcher plants in order to make the model work? When we are thinking of the evolutionary origin of the Utricularia trap, consider how difficult it would be to understand the origin of the aquatic Aldrovanda snap-trap, if the Venus Flytrap (Dionaea muscipula) had gone extinct from its small home range in the Carolinas a few hundred years ago, before it was catalogued. Darwin noted in 1875 that "[i]t is a strange fact that Dionaea, which is one of the most beautifully adapted plants in the vegetable kingdom, should apparently be on the high-road to extinction." Many carnivorous plants are squeezed into highly specialized niches and have very restricted distributions, and, as carnivorous plant enthusiasts are all too aware, this means that the danger of extinction is high.
Initially, this may appear to be a speculative and complicated model. However, at every stage the model is supported by analogies to living traps and/or direct phylogenetic evidence, and no unusual evolutionary processes seem to be required even for the most extraordinary trap of Utricularia. Most importantly, I think, is that the model is able to incorporate all of the carnivorous plant traps into a simple scheme of niche specialization (see table), and in this context the Utricularia trap no longer seems so unusual.
(For a draft review paper on this topic, please email Nick Matzke at matzke@ncseweb.org. Comments are also welcome -- especially if you can come up with a better model!)
References
Darwin, C (1975). Insectivorous plants. London, John Murray, pp. 356-358. Free online here: http://pages.britishlibrary.net/charles.darwin3/insectivorous/insect_fm.htm
Heads, Michael (1984). "Principia Botanica: Croizat's Contribution to Botany." Tuatara, 27(1): 26-48. A transcript of the article is free online here: http://www.sciencebuff.org/principia_botanica.php
Jobson, R.W., et al. (2004). "Adaptive evolution of cytochrome c oxidase: infrastructure for a carnivorous plant radiation." PNAS, 101(52), 18064-18068. The paper is free online here: http://folk.uio.no/victoraa/Jobson_2004.pdf
Lloyd, F. E., 1942. The carnivorous plants. Chronica Botanica, Waltham, Mass.
by Tony Gridley
| My brother recently moved into a house in San Francisco that happens to have
a greenhouse in the backyard, and in this greenhouse
for some reason is a bathtub. So, for Christmas last year I gave him a Sarracenia flava
that had been sort of poking along on my fire escape since I bought it from the California Carnivores
table at the San Francisco Ferry Building awhile back. I have said in the past that everyone should
grow Sarracenia because after all they are self-fertilizing potted plants that can't be overwatered, but
I say this partly in jest and was not at all prepared for this fairly spectacular picture,
accompanied as it was by the question,
"Was this what was supposed to happen?"
Obviously I will soon be burning my CP library and buying another bathtub for my apartment...... |
by Stephen Davis
I keep trying to find ways to make my carnivorous plant collection more interesting to non-CP people. I've found that most people look for a moment and then go on if the plants are not displayed well. If the plants are displayed well, they will stop, look, and sometimes actually notice the plants and start to appreciate them.
At the last BACPS plant show I purchased a pot of incredible pings from Phil Faulisi. They were in a white rectangular pot, about 2 inches high, that Phil had put a copper band around. The effect was that it didn't look like a plastic pot, and although the flowers were the main draw, the pot didn't look all that bad either.
However, as with all things, I decided I could not let a good thing go and I found a really nice pot at a store on my way back from a ski trip that I thought would look even better. The problem was that Phil had told me that that type of ping does better in a shallow pot, which I believe more closely duplicates the conditions they grow in in the wild. Many Mexican pings are found growing on wet seeps on rocks, hanging on to very little soil.
Phil explained to me that "one of the reasons this is such a superior way to grow pings is that the large surface area allows the rosettes to develop fuller, flatter rosettes due to the extra surface humidity. You don't have to worry about the leaves of larger species folding over the edge of the pot. They can grow undisturbed to full potential and look so much better."
My solution was simple. When I bought the pot, I also bought an extra saucer. I tried several sizes and decided on one that fit in the pot about 2 inches below the rim. Since I didn't want water to flow under the new false bottom I used silicon sealant from the hardware store all the way around the lip of the saucer.
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The pot is on the right. Of the two saucers on the left, one will sit under the pot like you would expect, but the other will go inside the pot, keeping the soil only a few inches deep. |
Using window screen and silicon sealant, I plugged the hole in the bottom of the pot. In theory, no water should get down to this level anyway, but just to be sure... |
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Here I am putting the saucer that would normally go in the bottom of the pot, into the pot. |
Here it is fitted in. By looking at my fingers you can see about how deep the pot will now be with its false bottom. |
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Here I put caulking around the rim of the saucer. |
OK, done. Now for a pile of perlite in the center, then cover that with the usual 50/50 peat/sand mixture. |
I put a small mound of perlite in the center of this, with the hope that it would give more space for water to be stored and ease the watering frequency needed to keep such a shallow pot wet enough for carnivorous plants. Then I used the usual mixture of 50/50 peat/sand, creating a small mound over this. Then I transferred the pings.
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So far they seem to be doing OK. They have bloomed and grown well. I have nothing to compare them to, so I can't say this is a superior way to grow them, but it looks good and I hope to enter them into the BACPS plant show later this year! |
by Doris Quick
Here it is, the ultimate accessory for the committed (or is it commitable) CP collector.
http://www.clarkmade.com/imagesshow/pitcherplant.jpg
September 11: BACPS Annual Show and Sale, Lakeside Park Garden Center, Oakland
September 25: UC Berkeley Botanical Garden Fall Sale
Summer at Filoli -- Arthur Yin; Sarracenia flava in bathtub -- Bill Gridley; all other photos -- Stephen Davis
The BACPS Newsletter is a quarterly publication produced by the Bay Area Carnivorous Plant Society. For more information on membership, subscriptions, or events, please visit our website: www.bacps.org.
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