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Post by mannyherrera on May 9, 2007 20:48:20 GMT
Barry,
Thanks for the links. I enjoyed your travel stories. Great pics too. I never imagined var montana to be growing like that.
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Post by Dave Evans on May 11, 2007 3:40:19 GMT
Dear Stephen, I have not actually read the paper, but I understand how genetics work. The results show that each subspecies of S. rubra are each other's closest relatives. This confirms something we already knew, giving us evidence they are testing the right part of the DNA. (background notes: The gene(s) they are looking at are not effected by evolution, which can speed up or slow to a stop, but by time. By counting the mutations, which occur at a near constant rate, these genes act almost like a clock showing how long it has been since their ancestors stopped interbreeding as compared against other closely related species or individual organisms--it doesn't spell out, "Hi! I'm a new species" or, "hey, we're the same thing" using this data to say S. rubra subspecies haven't evolved is a big stretch) It also shows that S. oreophila is probably of hybrigenic origin. Based on its morphology, it is probably derived from populations of S. rubra and S. flava hybridizing together. These "mixed" populations then suffered massive attrition which produced the species S. oreophila with it's extremely fragmented and small range. --Yep, my thoery could be complete bunk. What do you think? When the various populations of S. purpurea were tested, the data show that on this one point, S. purpurea and S. rosea are not closely related. But there is no chance that this gene was "donated" from a different species, a la S. oreophila. The only way it got to be that different was by S. rosea having very little to with the rest of S. purpurea for a very long time. Much longer that the six (one is not named) subspecies of S. rubra had during which they spread to their current ranges. This data also shows the name S. purpurea venosa var. burkii to be taxonomically invalid. The reason for this is because S. purpurea venosa has nothing to do with S. rosea, because they are not directly related. S. rosea shows a range diversity, it's own range of diversity separate from S. purpurea, which in turn has it's own range of diversity. The diversity shown by both species has evolved independently. It isn't that S. rosea just has pink flowers--That would be a joke to call it a separate species. There are populations with cream flowers too. Please show me some S. purpurea with cream colored flowers. It is well documented that Sarracenia keep their flowers away from the carnivorous leaves, either by height differences or by flowering before the first carnivorous leaves open, so the pollinators don't get eaten by mistake. Right there should be a red flag indicating you're looking at something fairly different... The flower color is just a hint. Look at the structure of the plant. Why is S. rosea different in this regard? Saying, "Oh, it is just a purp; it is not any different", just doesn't cut it. It appears to me that S. purpurea uses the height of the flowers, while S. rosea uses timing. I have been growing both species next to each other for ten years now. They are not the same, or even very close. During the winter, most of the leaves of _S. rosea[/i] "melt", this doesn't happen with any variety of S. purpurea. S. rosea is not flower bud hardy in New Jersey--you have to protect the plants over winter in a cold frame to get a nice crop of flowers in the spring, same as for S. psittacina, but S. psittacina is more flower hardy than S. rosea.. S. rosea is the least hardy of all Sarracenia, while on the other hand, most everyone knows S. purpurea is the most hardy species. This does not raise a Red Flag in your mind? Next, I'll hear that S. purpurea is both the most cold hardy species and also is the least cold hardy species of Sarracenia? Does that make sense, or even seem congruent??? what, the Neyland paper? I don't understand what you mean Dave your pictures to me contradict your point about structure, apart from flower colour I see very little discernible difference between the plants shown. How would you describe the difference?
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Post by Aidan on May 11, 2007 10:19:50 GMT
I have not seen the Neyland paper and am not qualified to comment. However, your observations of physical characteristics of the plant differ significantly from my own:
Flowers are held well above functional trapping leaves.
Funtional trapping leaves are retained throughout the winter.
New Jersey is significantly north of the natural range and so it is hardly surprising that S. purpurea ssp. venosa var. burkii may not prove "flower bud hardy" in your location.
Minor morphological differences do not a new species make.
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Post by Michael Catalani on May 11, 2007 12:15:11 GMT
I have not seen the Neyland paper and am not qualified to comment. However, your observations of physical characteristics of the plant differ significantly from my own: Flowers are held well above functional trapping leaves. This is not the case of true S. roseas in the wild. Their flowers are freakishly short, sometimes with only an inch or two of scape. Although the flowers do rise just above the pitcher height in some plants (because in some they do not), they have by far the shortest flowers in the entire genus. Some of my S. roseas have flowers in which part of the flower rests on the ground. S. purpurea ssp venosa, on the other hand,, have flowers that tower well above the plant. Cultivated S. rosea plants may have been crossed with other S. purpureas, in which case could cause the scapes to be longer and the flowers to be taller. But in the wild, this isnt the case. The flowers are always freakishly short, and I havent spotted a single S. rosea plant in the wild that had a flower that rose more than a couple of inches above the pitcher height. Yea, try telling that to the Nepenthes guys ;D Actually, if you were to agree that S. oreophila and S. flava should remain split, then one could make the same statement about S. rosea. S. oreophila has two stable traits that separate it from S. flava; flower height and curved phyllodia. All other traits are variable within wild stands of S. oreophila. There are S. oreophila that have as well developed columns, hood flaps, coloration, flower size and petal color as that of S. flava. Its just that in S. oreophila, these traits are variable to where many plants dont have as well developed "everything" in one package. But the differences can be extremely trivial withiin some stand of S. oreophila.
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Post by Aidan on May 11, 2007 13:54:45 GMT
I guess that would explain why of a dozen wild-seed grown plants only one has a "freakishly short" flower scape this year...... Even if I concede the point, flower structure is the same. I'm still waiting to hear a remotely convincing argument to elevate S. purpurea ssp. venosa var. burkii to species status. So far all I hear are people who want there to be a new species. The fallback argument of "Well, the DNA says..." should as Stephen has pointed out be treated with extreme caution.
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Post by rsivertsen on May 11, 2007 14:47:22 GMT
I'm inclined to agree with you Aidan, if we elevate this color form to a new species status, we might as well also elevate the var. heterophylla (the anthocyanin free, yellow flowers and all) form to another species too. Also, I have seen this short flower scape occur on some purps from time to time, depending on the temps and other conditions during early Spring, and again, genetic drift of various populations can account for these subtle differences, but doesn't necessarily warrant new species status.
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Post by Michael Catalani on May 11, 2007 21:46:10 GMT
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Post by Dave Evans on May 11, 2007 23:50:17 GMT
Dear Adian, Michael and all, Considering my experience viewing these plants in the wild and having grown them for about ten years, I have no doubt that each test conducted will continue to show these two taxa are different species. The texture of the leaf tissue is even different... The flowers are easily the most different physical aspect, the various flowers parts are all different sizes when compared against flowers of S. purpurea. Why do folks keep saying these two species do not look different? Are you sure you are actually growing them? The physical shapes of various parts of the plants are consistently different. Each time I mention they are physically shaped differently, someone says, but it's just a different flower color what is the difference? It is getting a bit annoying... Rich? You want to separate N. ventricosa from N. ventricosa based on minor differences in pitcher shape, leaf length, and clonal robustness (when most other species show so much more diversity), but when we talk about just about every single thing you can measure on a plant not matching, it some how doesn't count because it is S. purpurea? There is no physical differences between S. purpurea purpurea and S. purpurea purpurea heterophylla, there is also no evidence of any sort of separation between the two, and they regularly interbred. Comparing these two situations just goes to show... uh, nothing... Why even bring it up to use as a comparison? You know, there is hardy any difference between S. purpurea purpurea heterophylla and S. purpurea venosa, why are they even in separate subspecies? These should be lumped together. See? I'm a lumper. But I will not mix the diamonds in with the coal just because they are both forms of carbon... Yeah, I skipped from plants to chemicals, but I hope I illustrated my point here... Yes, both S. p. and S. r. have recumbent pitchers. But is that what actually defines S. purpurea? If so, I can see why it would be impossible to separate the two... I am separating them because of the way the two taxa relate to each other, this view is not based on how I relate to them. Please provide some evidence that they should be put together as one, without making up the evidence (Schnell); or ignoring what has already been documented (McPherson) as some authors have. The two subspecies S. purpurea purpurea and S. purpurea venosa are based on someone's fancy that the "northern" plants are "different" from the "southern" plants. I am not sure how they came up with this, but it was not the direct result of studying the plants, as they do not show any real separation; historically, genetically nor by physical characteristics or even by their range. It was a theory which has been debunked by research and observation. Same goes for the theory S. purpurea venosa burkii is part of S. purpurea.
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Post by Aidan on May 12, 2007 2:18:51 GMT
Not the greatest photograph in the world, but it proves a point. The photo was taken yesterday. All bar a couple of the plants in the tray were grown from wild seed. Virtually all the pitchers are last years growth. New leaves are obvious. With the exception of one "freakishly small" scape, flowers are held at heights not untypical for S. purpurea.
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Post by rsivertsen on May 12, 2007 2:19:17 GMT
Dave, there's much more to the differences between the true species of N. venticosa and the ones called "red ventricosa" commonly in cultivation; the peristome, leaf shape and length, pitcher size, and most importantly, they are highland growers, doing best in cool conditions, while the various red forms do best in warmer conditions; I've had both forms growing outside at one time, and after a mild overnight frost, all the red forms were dead, while the true species, the porcelain form didn't even show any signs of damage, and kept right on growing.
I still feel that S. purpurea forms are just various, yet significantly different geo-type forms of S. purpurea. (and yeah, I'm a "Nepenthes guy" too! - LOL)
Over the past 30+ years, I’ve seen thousands of them, in hundreds of sites from the Southeast states, to the NJ Pine Barrens, up to Maine, and westward from Pennsylvania to West Virginia, to the Great Lakes region, and into Canada. In almost every population, I see subtle variants in flower color, size of the hood, the undulations in the hood, and color of the pitcher, and certainly, a few sports; it doesn’t elevate them to new species status in my opinion; but that’s just me.
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Post by Dave Evans on May 12, 2007 4:24:13 GMT
Dear Aidan, Those are all pure S. rosea. Some growers have been making intergrades, your's are not. And yes, those flower stalks are about half the height S. purpurea typically reaches. Look at the styles, they have different portions when compared with S. purpurea, the level of difference is easily at the same level of difference shown when comparing S. minor to S. flava. Dave Evans All bar a couple of the plants in the tray were grown from wild seed. Virtually all the pitchers are last years growth. New leaves are obvious. With the exception of one "freakishly small" scape, flowers are held at heights not untypical for S. purpurea.
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Post by Dave Evans on May 12, 2007 7:09:18 GMT
Dear Rich, I thought I knew what you're talking about, but now I am not sure I am familar with these 'red form' N. ventricosa you have been refering to... Dave E. Dave, there's much more to the differences between the true species of N. venticosa and the ones called "red ventricosa" commonly in cultivation; the peristome, leaf shape and length, pitcher size, and most importantly, they are highland growers, doing best in cool conditions, while the various red forms do best in warmer conditions; I've had both forms growing outside at one time, and after a mild overnight frost, all the red forms were dead, while the true species, the porcelain form didn't even show any signs of damage, and kept right on growing.
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Post by Dave Evans on May 12, 2007 7:41:38 GMT
Dear Rich, I agree. It appears that the main physical differences S. purpurea shows is based on the soil conditions. I. E. the same plants will look different, depending on the soil they are growing in. Now, regardless of the soil they are in, the plants from Florida and surrounding areas are always different and never match those from northern GA and northward. Please, show me a northern plant that looks like S. rosea. Also, I would really like to see a S. rosea which looks like a S. purpurea. If, as you say, the differences noted can be attributed to genetic drift, this should be easy to do. Good Growing, Dave Evans Over the past 30+ years, I’ve seen thousands of them, in hundreds of sites from the Southeast states, to the NJ Pine Barrens, up to Maine, and westward from Pennsylvania to West Virginia, to the Great Lakes region, and into Canada. In almost every population, I see subtle variants in flower color, size of the hood, the undulations in the hood, and color of the pitcher, and certainly, a few sports; it doesn’t elevate them to new species status in my opinion; but that’s just me.
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Post by Alexis on May 12, 2007 21:37:10 GMT
To be fair, S. oreophila flowers along with the pitchers opening and often at a similar height (perhaps because of the shorter growing season because of the soil drying) and S. minor flowers late with the blooms surrounded by pitchers.
With regards to pitcher shape, there is far more physiological differenes between ssp. purpurea and ssp. venosa than with burkii and venosa.
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Post by Dave Evans on May 13, 2007 9:16:48 GMT
I think this is the case because S. oreophila is a hybrid which is still evolving, or going extinct. Humanity came along and noticed it before it had the chance to straighten up. In S. minor the flowers are below the pitcher openings, around half as tall as the leaves. Also, because of the color, they contrast with the leaves. Not sure how insects see this though... S. p. v. has a smallish range compared to S. p. p., but it has more genetic diversity. You can find plants of S. p. v.which have both venosa and purpurea shaped leaves at the same time, I don't know what conditions prompt the plants to express this... Daylength? To be fair, S. oreophila flowers along with the pitchers opening and often at a similar height (perhaps because of the shorter growing season because of the soil drying) and S. minor flowers late with the blooms surrounded by pitchers. With regards to pitcher shape, there is far more physiological differenes between ssp. purpurea and ssp. venosa than with burkii and venosa.
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