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McPherson's burkii


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#1 Dave Evans

 
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Posted 07 March 2012 - 02:56 AM

Why? S. rosea is a subspecies of purpurea, not a color morph!

This continues the uneven handling of taxa by claiming so erronously that, "S. rosea are often insufficient for reliable identification, both in the wild and in cultivation."

This really is "junk science" and the first thing I see in Stewarts new books...

Then we have, "S. jonesii" also being described the same exact way! Okay, on one stewart evenly places jonesii as a subspecies of rubra; on the other claims this subspecies of purpurea is just a form, a color morph. What??? If he can't tell purpurea from rosea, you shouldn't trust any of his opinions.

#2 Ordovic

 
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Posted 07 March 2012 - 09:10 AM

Are you sure that's what it says? Please could you quote the lines or pages & paragraphs that illustrate your point.

I'd like to point out that varieties are supposedly valid taxons not merely colour morphs even when colour is the distinguishing character. However, I personally feel McPherson has got this wrong; that the morphological differences (i.e. short flower scapes etc.) are sufficient to elevate this taxon to subspecies level in line with the S. rubra complex and the other S. purpurea ssp.

Mind you, 'burkii' is clearly a S. purpurea and until it flowers kind of difficult to separate from ssp. venosa and to my eyes obviously not a different species.

Sarracenia purpurea ssp. burkii?

But that's my opinion.

Edited by Ordovic, 10 March 2012 - 08:51 AM.


#3 Alexis

 
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Posted 07 March 2012 - 13:08 PM

If it's to be elevated to a whole new species based purely on morphological differences, I think McPherson and Schnell do a good job of debunking them.

Whether it should be a subspecies is another debate, but a whole new species is bizarre when some examples are indistinguishable from some venosa clones when not in flower.

#4 Dave Evans

 
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Posted 07 March 2012 - 15:04 PM

The reason some cannot be told apart is because they are horticultural hybrids between. S. rosea and S. purpurea venosa.

Purpurea and venosa belong in one subspecies, rodea another. Several studies Stewart didn't bother looking at demonstrate exactly how different S. Rosea is from purpurea, they don't even make the same chemicals. S. rosea is what is called a cryptic species, it was produced not by natural selection but from being separated from pupurea for tens of thousands of years. Genetic drift takes over as the main mechanism. It is purpurea's closest relative; but it has changed its interal chemistry quite a bit, more than its outer appearence. Since it still "looks" like purpurea hardly makes it just a color-morph. S. rosea contains within it differing populations which have their own varieties and forms. This rank of "form" makes no sense.

There is no direct connection; genetic, ecological, physiological, between S. purpurea venosa and S. purpurea venosa burkii, there never has been except in Dr. Schnell's and now McPherson's books; and long, long time ago.

#5 Phil Green

 
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Posted 07 March 2012 - 16:49 PM

Dave - there will always be arguments over exactly at what rank within a species something is classed. The main thing is, that this work (not just by Stewart) places rosea back in purpurea and jonesii back in rubra etc. The real 'junk science' was trying to claim them as seperate species in the first place.

#6 Alexis

 
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Posted 07 March 2012 - 18:57 PM

The reason some cannot be told apart is because they are horticultural hybrids between. S. rosea and S. purpurea venosa.




Look at the SC venosa on page 467 and the AL burkii on page 478. I can see individual pitchers on both plants that appear identical to their opposites.





#7 Dave Evans

 
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Posted 07 March 2012 - 19:56 PM

Wrong Phil, there never was any solid argument to separate jonesii from rubra. On the other hand, there is plenty of compelling evidence to separate rosea from purpurea. Mixing these two different situations as the same case is ridiculous. Rosea has been studied every which way and the only authors who combine them are Schnell and Stewart.

#8 Dave Evans

 
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Posted 08 March 2012 - 02:13 AM

Alexis, I'll look at those photos, but my first thought is that the photos where not taken in the same season... place the plants next to each other and you will not have any trouble telling 'em apart.

#9 Ordovic

 
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Posted 08 March 2012 - 11:05 AM

...it was produced not by natural selection but from being separated from pupurea for tens of thousands of years. Genetic drift takes over as the main mechanism.


This is a spurious claim. If the two types are separated then they're subject to different climatic and ecological environments. Selection cannot be ruled out for the morphological and physiological differences and is inevitably a factor.

... It is purpurea's closest relative; but it has changed its interal chemistry quite a bit, more than its outer appearence. Since it still "looks" like purpurea hardly makes it just a color-morph. S. rosea contains within it differing populations which have their own varieties and forms. This rank of "form" makes no sense.


I couldn't agree more.

There is no direct connection; genetic, ecological, physiological, between S. purpurea venosa and S. purpurea venosa burkii, there never has been except in Dr. Schnell's and now McPherson's books; and long, long time ago.


Apart from the fact that they're more closely related to each other (including S. purpurea ssp. purpurea) in all these ways than to any other Sarracenia and form a natural clade apart from the other species. This monophylletic relationship means S. rosea can legitimately be subsumed under S. purpurea but that S. p. ssp. venosa and S. p. ssp. purpurea are more cloesly related to each other than either is to S. rosea doesn't alter this, only that S. rosea would have to be given equal taxonomic rank as subspecies and not included within S. p. ssp. venosa as a variety.

That said, that Neyland, Ray and Mark Merchant (2006) couldn't resolve the "alata-rubra-oreophila" complex would suggest either treating those as a single species or (more reasonably), separating S. rosea for the sake of consistency.

#10 meizwang

 
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Posted 08 March 2012 - 23:58 PM

This S. rosea in situ from okaloosa Co, FL looks very similar to venosa:
Posted Image

And this S. rosea in situ from Baldwin Co, AL looks very much like venosa as well:
Posted Image


This S. rosea, on the other hand, looks like S. rosea. This one is in situ from Liberty Co, FL:
Posted Image

Just adding more fuel to the discussion :preved:

#11 Dave Evans

 
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Posted 09 March 2012 - 02:35 AM

Take a close look at the veining in the lids, it is unique to "burkii". The flowers and the thickness of the lip are variable, but the lip is nearly always wider and the flowers are different as everyone knows. But the seed count is different and the seeds are different too. There are so many things which indicate a separate venosa and burkii.

I was just potting up rosea and venosa seed, yes, even the seeds are different; similiar as to all sarracenia seed, but different enough to notice and match different lots to the correct species.

#12 Alexis

 
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Posted 09 March 2012 - 10:23 AM

I agree Dave, but the differences are not enough to make it a whole new species in my view. I'm all for purpurea ssp. purpurea / venosa / burkii (or rosea).

#13 meizwang

 
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Posted 09 March 2012 - 17:14 PM

Take a close look at the veining in the lids, it is unique to "burkii". The flowers and the thickness of the lip are variable, but the lip is nearly always wider and the flowers are different as everyone knows. But the seed count is different and the seeds are different too. There are so many things which indicate a separate venosa and burkii.

I was just potting up rosea and venosa seed, yes, even the seeds are different; similiar as to all sarracenia seed, but different enough to notice and match different lots to the correct species.



Hi Dave,

can you elaborate on the unique veination of S. rosea? Here's some more pics for fun/comparison:

S. rosea Mobile Co, AL in cultivation:
Posted Image

S. purpurea venosa Old Dock, Columbus Co, NC:
Posted Image

S. purpurea ssp. venosa Bell Swamp, Brunswick Co, NC:
Posted Image

S. purpurea ssp. purpurea wellington and Huron Co, ON:
Posted Image

S. montana Transylvania Co, NC:
Posted Image

#14 Ordovic

 
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Posted 10 March 2012 - 09:10 AM

S. montana Transylvania Co, NC:


Don't you mean S. purpurea ssp. venosa var. montana???
:whistling:

By the way I know it's not really justification but I think my greatest objection to S. rosea as a separate species is probably the name; don't like it. Naczi et al should have called it S. burkii. I know they were trying to avoid confusion but we are talking about the same plants and actually giving them a brand new moniker makes it worse, because now not only is everyone arguing over its taxonomic rank but also what to call the thing.

Okay then, I'll be quiet now.

#15 meizwang

 
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Posted 10 March 2012 - 15:19 PM

Don't you mean S. purpurea ssp. venosa var. montana???
:whistling:

By the way I know it's not really justification but I think my greatest objection to S. rosea as a separate species is probably the name; don't like it. Naczi et al should have called it S. burkii. I know they were trying to avoid confusion but we are talking about the same plants and actually giving them a brand new moniker makes it worse, because now not only is everyone arguing over its taxonomic rank but also what to call the thing.

Okay then, I'll be quiet now.



haha, nope, I mean S. montana :sun_bespectacled:

#16 Dave Evans

 
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Posted 11 March 2012 - 03:20 AM

As an aside, I'm not sure about S. purpurea venosa var. montana. I'm thinking it is more likely S. purpurea purpurea var. montana...

#17 meizwang

 
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Posted 13 March 2012 - 03:31 AM

As an aside, I'm not sure about S. purpurea venosa var. montana. I'm thinking it is more likely S. purpurea purpurea var. montana...


When you get to the Virginia, New Jersey, etc. areas, there seems to be some purp. purp and venosa integrades. Perhaps something similar happened with montana-it seems to resemble both in some ways.

#18 Dave Evans

 
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Posted 13 March 2012 - 22:47 PM

When you get to the Virginia, New Jersey, etc. areas, there seems to be some purp. purp and venosa intergrades. Perhaps something similar happened with montana-it seems to resemble both in some ways.

That is what Schnell says... What I see is one kind of purpurea from Delaware up into New Jersey Pine Barrens up along the coast and into Canada; a second in the Southern Area of Virginia, North and South Carolina and the northern edges of Georgia; and a third kind around the Great Lakes; all of which being S. purpurea purpurea.

The original idea behind S. purpurea venosa var. burkii is that S. purpurea venosa is found from Virginia down into the Gulf Coast. However, there is no S. purpurea venosa in the Gulf Coast. Multiple botanists have exhaustively reviewed all the specimens of S. purpurea from Gulf Coast herbariums and haven't turned up a single example of S. purpurea venosa. All are S. rosea. This means the main reason (the theory) for this naming structure, S. purpurea venosa var. burkii, isn't valid. There is no venosa in the Gulf Coast, this is a fact and McPherson cannot talk his way around it. That boat has already set sail and is out to sea. Venosa appears more consistent as a variety of S. purpurea subsp. purpurea. S. rosea should probably be placed back under S. purpurea as a subspecies, even if it is a “cryptic species”. What would be nice to know, the exact nature of the relationship between S. rosea and S. purpurea venosa? Does venosa represent ancient hybrid between proto-rosea and purpurea purpurea? In that case, each one would be a distinct subspecies...

I haven't any idea about the north western purpurea...

For for further information:
http://en.wikipedia....species_complex

Yes, it has changed more on the inside, than on the outside. This is essentially what a "cryptic species" is.

Edited by Dave Evans, 14 March 2012 - 00:25 AM.


#19 Alexis

 
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Posted 14 March 2012 - 10:17 AM

There doesn't have to be any examples of a species in the vicinity to make a variety null and void though. That's like saying flava var. maxima doesn't exist in Virginia because there are no var. atropurpurea plants in the state.

I agree that the three 'types' may need rearranging with rosea/burkii being elevated above variety status, but not as a species.

Three subspecies of purpurea, with montana remaining as a variety of venosa, seems the clearest designation to me.

#20 Dave Evans

 
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Posted 15 March 2012 - 22:37 PM

There doesn't have to be any examples of a species in the vicinity to make a variety null and void though. That's like saying flava var. maxima doesn't exist in Virginia because there are no var. atropurpurea plants in the state.

Not really, because the var. burkii is *under* venosa.

What I'm like saying is similar to, "there isn't any flava maxima because there isn't any flava." See the difference?

There is no such plant as S. purpurea venosa var. burkii. The name refers to a plant which is not part of S. purpurea venosa. As has been previously demonstrated several studies, all of which performed on this plant have clearly indicated it is a cryptic species. To me this means it is about 9/10th's of the way to becoming a separate species, so it is currently acceptable as the stand alone cryptic S. rosea or it is an un-named sub-species of S. purpurea. "Var. burkii' is not acceptable.

Edited by Dave Evans, 15 March 2012 - 22:46 PM.