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Post by Michael Catalani on May 13, 2007 14:23:48 GMT
S. oreophila probably flowers after pitcher opening because of the dangers of early spring freezes which can occur regularly where they grow. Frosts can damage the emerging flower buds, freezes can kill them outright.
S. oreophila are typically in petal from the 1st week of May til the last week in May in Alabama, with the southern plants in petal earlier May and the northern plants in petal in late May. By then many of the best pitchers have been open for a few weeks. But this delay can get them past most of the harsher cold spells that can hit while the flower buds are emerging.
But it doesnt always help. There was a report a decade or two ago that nearly all of the wild S. oreophila flowers in Alabama had been killed due to a hard freeze that occured that year.
This may be a good reason why the flowers are as tall or taller than the pitchers. Since the pitchers have already been open a while before flowering, then the plant would want to elevate the flowers for better advertising before they open, or only a very few flying pollinators would ever make it down to the depths of shorter flowers when a mass abundance of open pitchers would be detouring their path.
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Post by Alexis on May 13, 2007 18:57:36 GMT
Interesting. Are pitchers and flower buds just as vulnerable to frost? I remember a post a few weeks ago where someone's emerging pitchers were unaffected by frost, but the just opening pitchers suffered. The waxiness of young pitchers might have offered some resistance.
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Post by Michael Catalani on May 13, 2007 21:31:11 GMT
Interesting. Are pitchers and flower buds just as vulnerable to frost? In my experience (and this year was another banner test case with our early spring hard freeze) the flower buds are much more affected by frosts and freezes than the pitchers of most species. Every Sarracenia flower I had that was left unprotected this spring either rotted, aborted growth, or was deformed to the point where I'm not sure how functional they will be. Some pitchers ended up getting freezer burn on the top and deformed/stopped growing, but a majority of all pitchers from all species survived. So all flower buds were afftected, but only a few pitchers. The temperatures dropped to the low 20's farenheit for two nights, which caused the damage this year.
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Post by Dave Evans on Sept 27, 2007 22:36:22 GMT
Hello Aidan, Would you mind explaining why they should be considered the same species? I'm probably not alone in saying that I will take a lot of convincing that S. purpurea ssp. venosa var. burkii deserves elevation to species status. A separate race or subspecies perhaps.
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Post by Aidan on Sept 27, 2007 23:01:13 GMT
Deja vu...
I believe that Stephen (gardenofeden) made the case quite succinctly and his knowledge of plant taxonomy is considerably greater than my own.
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Post by Dave Evans on Sept 28, 2007 2:56:01 GMT
Hi Manny, Sorry I have taken so long to reply... There are three populations (or kinds) of S. purpurea in Georgia. There are the mountain purps, S. purpurea montana in the northwest. S. purpurea venosa in the northeast. Then there is S. rosea in the southwest. The historic gap between S. purpurea venosa and S. rosea has been there for several ice-ages, since the glaciers did not reach that far south. While an ice-age could have split species, it would seem S. purpurea and S. rosea were already separate before this process started. It is believed that as the glaciers melted last time, they pulled small samples of S. purpurea north with them. Supposedly this process creating S. purpurea purpurea, but I really don't understand how this mechanism worked... Sounds a bit dodgy to me. I wonder if or how many species of Sarracenia were destroyed by the ice-ages... Maybe there were species closer or more reminiscent of Heliamphora. Hello Stephen and Aidan, there are over a dozen morphological and ecological differences between S. purpurea venosa and S. purpurea venosa burkii... I don't know for certain that S. rosea is completely a differently species, but it would be nice for these differences to actually be discussed, instead of being discounted. A fat lip. What? How about how they have different chemicals in them? Give me an example of another Sarracenia species with such divergent characteristics. And yes, I am completely familar with various random mutations and backcrossed hybrids of S. luecophylla, S. flava, S. alata, S. rubra, S. alabamensis, ect. None of which covers the differences between S. purpurea venosa and S. rosea. Sure yellow flowered plants of typically red flowered species can be found in a couple of locations, mixed with typical examples of the species. This some how discounts the fact the differences between S. r. and S. p. are consistent over the entire range? Hi Dave. Thanks for bringing this up. I have been trying to sort out the purpurea in Georgia question for some time. I have seen people with purps labeled "Georgia", but they have no idea where they came from. I'm not looking for exact location data, just general range info. Does purp venosa grow only in NW GA? If then, is it only the var montana form? I remember ABG doing something with purps from north GA. It seems the only purps in GA are found in the northern part of the state. Are there two forms? Or does var montana not grow in GA? I have never come across any purps in the southern portion of the state. And if there are any there, I assume they would be different than the northern GA forms. Perhaps a little more resembling of rosea. Sorry for all the questions, but this is a subject that interests me. P.S...I've never seen any purps in MS or LA either.
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Post by John Brittnacher on Sept 29, 2007 0:31:57 GMT
I don't think anyone has mentioned the Neyland and Merchant paper in Madrono 53(3):223-232, 2006. They did a molecular study of genetic differences in the Sarraceniaceae. The genes used typically are able to separate related species and probably before doing the project they assumed they would FINALLY figure out Sarracenia. Well it didn't work out that way which may be why the paper is in Madrono instead of AJB.
The bottom line of their data is they could distinguish separate six groups:
1) S. alata
2) S. rubra rubra / S. r. alabamensis / S. r. wherryi / S. r. jonesii / S. r. gulfensis / S. oreophila
3) S. leucophylla (borderline separation from group 2)
4) S. psittacina / S. minor / S. flava
5) S. rosea (S. purpurea ssp. venosa var. burkii)
6) S. purpurea purpurea / S. p. p. var. montana / S. p. venosa
Also groups 1-4 were very different from 5-6.
As much as I hate the name "S. rosea", should have been "S. burkii", I have to admit that morphologically it is as different from S. purpurea as any other of the tall species are different from each other and genetically it is different so S. rosea it is unless someone can show some other name has precedent.
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Post by Alexis on Sept 29, 2007 0:32:07 GMT
Can you give us an overview of your opinion of these differences between the two?
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Post by Aidan on Sept 29, 2007 1:01:39 GMT
John - Stephen commented on the molecular study earlier in the thread: Barry, I have got a copy of the molecular studies paper now and have had a good look. Yes, it does show burkii as separate to the other purpureas. BUT it also shows that there is no differentiation amongst the rubra complex, not even at subspecies level, so they are all just Sarracenia rubra (even alabamamensis and jonesii). It also shows no differentiation between rubra and oreophila, so should oreophila now be lumped in with rubra? Therefore we have to be very cautious about quoting extracts of this paper just to suit certain species if we ignore the implications for the others. What it does show is that the genus is still relatively new and actively evolving and so we have to be very cautious and coming up with brand new species...
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Post by Michael Catalani on Sept 29, 2007 1:03:31 GMT
I don't think anyone has mentioned the Nyland and Merchant paper in Madrono 53(3):223-232, 2006. They did a molecular study of genetic differences in the Sarraceniaceae. The genes used typically are able to separate related species and probably before doing the project they assumed they would FINALLY figure out Sarracenia. Well it didn't work out that way which may be why the paper is in Madrono instead of AJB. The bottom line of their data is they could distinguish separate six groups: 1) S. alata 2) S. rubra rubra / S. r. alabamensis / S. r. wherryi / S. r. jonesii / S. r. gulfensis / S. oreophila 3) S. leucophylla (borderline separation from group 2) 4) S. psittacina / S. minor / S. flava 5) S. rosea (S. purpurea ssp. venosa var. burkii) 6) S. purpurea purpurea / S. p. p. var. montana / S. p. venosa Also groups 1-4 were very different from 5-6. As much as I hate the name "S. rosea", should have been "S. burkii", I have to admit that morphologically it is as different from S. purpurea as any other of the tall species are different from each other and genetically it is different so S. rosea it is unless someone can show some other name has precedent. Wowsa, I am really surprised by two things here. The first is the separation of S. alata. I was kind of sure that this is a relatively new species of hybrid origin, so this is surprising that its not in a S. rubra or S. flava grouping. The second is the way S. leucophylla is separated by itself. When I see these plants in the wild, there is little stability in its traits. It hybridizes like crazy with any other tall Sarracenia that attempts to grow with it, to the point that other tall Sarracenias can not penetrate that well into its lower baldwin county, Alabama growing area. I would have thought for sure that it would be closely aligned with S. flava, S. rubra, and/or S. alata. Although they apparantly say there is a borderline separation the with S. rubra complex, I am surprised that there isnt a closer affinity with the S. flava or S. alata groups.
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Post by John Brittnacher on Sept 29, 2007 2:45:09 GMT
Wowsa, I am really surprised by two things here. The first is the separation of S. alata. I was kind of sure that this is a relatively new species of hybrid origin, so this is surprising that its not in a S. rubra or S. flava grouping. The second is the way S. leucophylla is separated by itself. They did lots of S. alata clones so I would believe the comparisons between S. alata and S. rubra. The difference from S. rubra / S. oreophila is minimal but significant in the way these things are judged significant or not. You still could be quite correct in the origin--it would depend on the raw data in a way that would not be apparent from what they published. (I wish I could post the article for you all to read but alas it is copyrighted and not otherwise available to non-members of the California Botanical Society unless you pay for a copy.) Where I have concern with the study is what exactly they used for source material for the other species. Sure they specify that but you are right, there is such huge variation within and between populations of the same species, doing anything like this is problematic without LOTS of plant samples and LOTS of gene samples. What amazes me is with all the hybridization and introgression between Sarracenia species that there actually are discernible species. I would guess from the plants I have grown from seed of S. leucophylla from named locations that the species is quite variable in flower and pitcher form and color. If this is from introgression with other species then the genetic analysis would reflect this by making it difficult to distinguish it from other species. As I said what they tested is minimally different from the S. rubra group. If they had used a different clone from a different location who knows what it would show. A genus were all the species can and do interbreed is a major nightmare for a molecular taxonomist and a minor one for a classical taxonomist. The distinction between species becomes very much dependent on personal opinion and a gestalt impression of the plants. (On the other hand this kind of situation is a delight for a plant breeder because of all the hybrids you can make.) As far as differences between S. rosea and S. purpurea purpurea, are we all agreed that there is absolutely no reason to consider them the same species based on morphology? It is the addition of S. p. venosa that makes the issue difficult? I think part of that has to do with growing conditions. In Davis, California, with plants grown outside it can take a few seconds to tell the plants apart when flower scapes are not present. Here in Ashland, Oregon, there is no question at all between S. rosea and S. purpurea purpurea. None. S. purpurea purpurea LIKES it here, S. rosea doesn't. I don't happen to have a S. p. venosa in Ashland.
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Post by John Brittnacher on Sept 29, 2007 2:57:32 GMT
BUT it also shows that there is no differentiation amongst the rubra complex, not even at subspecies level, so they are all just Sarracenia rubra (even alabamamensis and jonesii). It also shows no differentiation between rubra and oreophila, so should oreophila now be lumped in with rubra? Therefore we have to be very cautious about quoting extracts of this paper just to suit certain species if we ignore the implications for the others. What it does show is that the genus is still relatively new and actively evolving and so we have to be very cautious and coming up with brand new species... In the rules of science it is impossible to show two things are the same. You can only show things are different. This is the definition of the scientific method. That they were not able to discern differences between certain taxa could be because they didn't study the genes that are different or could be because there are no differences. You can't know which from the data. So because they could not show there are differences between taxa we say are different doesn't have any relevance to the differences they did find between other taxa.
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Post by Dave Evans on Sept 29, 2007 4:17:08 GMT
Hi John,
I do believe the data is related to genetic information passed only from mother to progeny, the process of making pollen basically makes it impossible for the information to be passed from the male parent to the next generation, which is why it is so good at showing how long it has been since the groups separated. I agree, the larger the sample studied more representative and complete your data will be.
I interpret this to indicate S. oreophila is probably the newest species (obviously newer than S. rubra!) in Sarracenia, the result of some species pollinating S. rubra, or being absorbed into the subsequent hybrid population via pollen donation only. Maybe the other species had a larger flower and the cross in the opposite direction had a very low chance for success.
It also indicates S. rosea is further removed from S. purpurea than S. rubra rubra is from S. rubra wherryi. Am I mis-interpreting the data? Calling S. rosea a subspecies of S. purpurea seems like a stretch, but how about a separate section within Sarracenia which has two species? This sort of device is used in many genera...
S. luecophylla (besides for S. p. and S. r.) is easily the most divergent morphologically, the seed heads open the opposite from from all other species. Perhaps S. luecophylla contributes more genetic information to the other species at a higher rate than it takes in, helping to maintain genetic isolation, through some mechanism we don't know about.?.
I'm also surprise to see S. psittacina, S. minor and S. flava in the same grouping... I always felt S. psittacina was closer to S. purpurea and less close to S. rosea... Of course I always have associated S. psittacina, S. minor and S. luecophylla in one group based on their using fenestrations as a lure. The strong separation of S. psittacina from S. purpurea is a surprise, as its closer association with S. flava!!! Really strange results.
I think way more genetic testing need be done before well founded conclusions can be made for the genus as a whole.
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Post by John Brittnacher on Sept 29, 2007 14:55:10 GMT
I double checked the Neyland and Merchant paper. They use nuclear ribosomal DNA (it is in the title). It changes in time faster than the mitochondrial genes so should give a better measure in closely related species and genera. In fact it worked perfectly to relate Sarracenia with Darlingtonia and Heliamphora (Sarracenia is more closely related to Heliamphora). Most Sarracenia species are too closely related to be distinguished with the techniques they used. Faster evolving genes will be needed. In the publication by Don Schnell describing S. p. v. burkii he only indicated the flowers as being the key difference. There may be other characters in his mind but what he cited as the distinguishing feature is the flowers. In the interview with Robert Naczi in CPN www.carnivorousplants.org/cpn/articles/CPNv31n3p87_92.pdfNaczi reiterated the flowers as being the key distinction. He waved his arms saying there are other differences but pay attention to the flowers. What this means for the evolution of the rest of the genus is that none of the other species evolved from S. purpurea in the form we currently know it. S. purpurea could have contributed genes via introgression but that is limited.
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Post by Alexis on Sept 29, 2007 16:18:58 GMT
Can someone explain how the pitchers of ssp. venosa and 'rosea' are regarded as very different, when to me the visual differences are small. The pitchers of ssp. purpurea are far more different from the others.
And as for flowers, ssp. purpurea blooms are quite a bit different from ssp. venosa.
How can ssp. purpurea, ssp, venosa and sarracenia rosea be any more valid than sarracenia purpurea, sarracenia venosa and sarracenia rosea??
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