# callosum or barbatum?



## Trithor (Dec 28, 2014)

These two plants are blooming next to each other on one of the benches. They are both growing very bright (a little too bright, but I don't have enough space to provide them with more shade, so they are forced to grow with my multis)
They are both from the same supplier, purchased a year apart. Both sold as barbatum. What do you guys think?


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## Rick (Dec 28, 2014)

They both could be barbatum, but the upper plant with more downswept petals could also be callosum var. subleavae (especially if the flower is smaller than the lower more wideswept flower).

The two are both found in Malaysia, and Cribb's book suggests the distinction is arbitrary.


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## Migrant13 (Dec 28, 2014)

Wow after looking at pictures of both on the net, I can't tell the difference. Perhaps the staminate will be the deciding factor but I am not sure I can tell. Either way, super plants and great growing!


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## troy (Dec 28, 2014)

I've gotta say you are an excellent grower, the display is excellent!! although l'm not a fan of these, l could see how others are


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## PaphMadMan (Dec 28, 2014)

Unless there are differences that are not apparent from your photos (we don't have equivalent head-on shots, nothing for scale, etc.) I would say these 2 plants are well within the normal variation I would expect to see between seedlings from the same pod. Unless you have information to the contrary, since they came from the same supplier under the same name they very well could be from one batch of seedlings. I see no reason to think they might be something different from each other, whatever they are labeled.

With the same provisions, with this appearance I would tend to call these callosum (perhaps sublaeve) rather than barbatum. But without more evidence I would keep them labeled as they came from the vendor.  I'm probably more comfortable than most with ambiguity in where to draw the line between related taxa, especially in a case like callosum/barbatum.


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## The Mutant (Dec 28, 2014)

To me, they look more like callosum than barbatum, but then I've just recently discovered how similar these species are, soo...

Whatever they are, they are gorgeously well grown plants. I really wish mine would grow like that.


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## tomkalina (Dec 28, 2014)

They appear closer to Paph. callosum or callosum v sublaeve than Paph. barbatum, which tends to have smaller, darker flowers with a more horizontal petal stance. If you Google Paph. barbatum, you'll find a few examples of what I would consider a true barbatum.


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## Trithor (Dec 28, 2014)

My understanding is that at the extremes of their range, they are easy (sort of) to distinguish. Barbatum from the south and callosum from the north, with those populations in between a bit of a mix. It is unclear as to wether the populations that lie in-between are separate population species or a batch of natural hybrids (my personal belief). However the truth of the matter is that the plants from this group show characteristics which are 'all mixed up'.


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## SlipperFan (Dec 28, 2014)

I am not a splitter on this one! Maybe genetics will someday tell.


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## abax (Dec 29, 2014)

I loooove 'em! You're such an accomplished grower that I feel inadequate.
I think they're callosum because I'm planning to buy a few in spring and
have been exploring photos on the net. Both are gorgeous.


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## SlipperKing (Dec 29, 2014)

For me these fit well within the callosum description. I really cannot see any barbatum influence in either clone as per "barbatum description" (as in far southern species)


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## Lmpgs (Dec 29, 2014)

Whatever they are, are just magnificent.


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## TyroneGenade (Dec 29, 2014)

I imagine that Cribb's book has a taxonomic key? If you follow the key, it should diagnose barbartum from callosum. If there is no difference, then these are barbatum as it is the older taxon (1823 vs 1886 for callosum) and callosum (and all its forms) would be junior synonyms to barbartum.

Bottom line: if there is no difference between callosum and barbartum then these are barbatum.


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## tomkalina (Dec 29, 2014)

Tyrone,

Both first and second editions of Cribb's The Genus Paphiopedilum agree on the separation of barbatum and callosum on the basis of petal stance, petal length, and dorsal sepal shape. Excellent drawings/photos of these differences in each edition.


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## labskaus (Dec 29, 2014)

Nice clumps = good growing!
Petal stance and colour, mainly, make these more callosum (sublaeve) than barbatum to me.


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## emydura (Dec 30, 2014)

Nice plants Gary. These aren't easy to grow that well.

I think this post demonstrates how ridiculous it is that barbatum and callosum are classified as separate species. The distinctions are subtle at best.


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## SlipperKing (Dec 30, 2014)

emydura said:


> Nice plants Gary. These aren't easy to grow that well.
> 
> I think this post demonstrates how ridiculous it is that barbatum and callosum are classified as separate species. The distinctions are subtle at best.



But this leaves two questions in my mind, which may never be answered. Where these two distinct species at one time that grew together and hybridized or one large spreading species that now has two distinct variants at opposite ends of its range?
It could be this was a large population of one species and with land masses shifting and a number of ice ages creating sea levels to rise and fall separated into three or more distinct species. now in modern times with current land masses as they are, two, callosum and barbatum are become one again. Leaving lawrenceanum and maybe others out of the picture for the moment.


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## PaphMadMan (Dec 30, 2014)

SlipperKing said:


> But this leaves two questions in my mind, which may never be answered. Where these two distinct species at one time that grew together and hybridized or one large spreading species that now has two distinct variants at opposite ends of its range?
> It could be this was a large population of one species and with land masses shifting and a number of ice ages creating sea levels to rise and fall separated into three or more distinct species. now in modern times with current land masses as they are, two, callosum and barbatum are become one again. Leaving lawrenceanum and maybe others out of the picture for the moment.



That's a very good summary of why "species" is an artificial category we try to impose on the real world, not a natural distinction.


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## Linus_Cello (Dec 30, 2014)

PaphMadMan said:


> That's a very good summary of why "species" is an artificial category we try to impose on the real world, not a natural distinction.



Yah! A fellow lumper.


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## Trithor (Dec 30, 2014)

It was during my early years as a med student that I became interested in paph species (82 to 87), and spent a fair portion of my vac time trying to find them in the wild. My family was split between Africa and Nederland, so every trip back home usually saw me taking the very long way home via SE Asia. I managed to see callosum and barbatum in the wild from the north of Thailand to the south of peninsular Malaysia. I unfortunately gifted my collection to another grower when I started with my specialty and no longer had any time to look after my plants. (It was only when I left medicine to start a timber import business that I started growing my orchids again). To cut a long story short, what I did notice was that the species are easily distinguished at the extremes of their distribution, but in the middle, they kind of blend, requiring a much more critical and observant eye than my own to differentiate.

Thank you all for your input. I posted the question to highlight the problem of species/nat hybrid/artificial hybrid being more widespread than just in the cochlo group which seems to get all the bad publicity, while there is a bigger problem in the most extensively hybridized group, which would call into question nearly every name from Maudiae onwards:evil::rollhappy:


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## PaphMadMan (Dec 30, 2014)

Trithor said:


> ...
> Thank you all for your input. I posted the question to highlight the problem of species/nat hybrid/artificial hybrid being more widespread than just in the cochlo group which seems to get all the bad publicity, while there is a bigger problem in the most extensively hybridized group, which would call into question nearly every name from Maudiae onwards:evil::rollhappy:



I would add that even a "pure" species, traceable back to specific well documented and characterized collected plants, could be unrecognizable after a few generations of selective breeding. And in virtually all cases we have only the most recent grower's word for what it should be.


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## TyroneGenade (Dec 30, 2014)

tomkalina said:


> Tyrone,
> 
> Both first and second editions of Cribb's The Genus Paphiopedilum agree on the separation of barbatum and callosum on the basis of petal stance, petal length, and dorsal sepal shape. Excellent drawings/photos of these differences in each edition.



Tom, can you share the diagnostic criteria here? What are the differences in petal stance etc... as Cribb describes them?

Thanks


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## tomkalina (Dec 30, 2014)

Tyrone,

P. callosum = "Petals strongly sigmoid, deflexed, usually more than 5 cm long; 
dorsal sepal large, often apparently ob-ovate, usually more 
than 5 cm wide."

P. barbatum= "Petals linear,spreading,less than 5 cm long; dorsal sepal ovate, 
usually less than 5cm wide." 

Not much to go by, but apparently enough for Cribb to separate them.


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## Stone (Dec 30, 2014)

Superb growing Gary! To me they are callosum all over.


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## paphioboy (Jan 2, 2015)

Very well grown specimens! Love this species..


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## Ozpaph (Jan 3, 2015)

wonderfully grown and flowered plants which I think look very similar.


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## Rick (Jan 3, 2015)

tomkalina said:


> Tyrone,
> 
> P. callosum = "Petals strongly sigmoid, deflexed, usually more than 5 cm long;
> dorsal sepal large, often apparently ob-ovate, usually more
> ...



But on pg 334 of his second editon:

"With a range of variation that is virtually continuous between the extremes of northern Thailand P. callosum and southern Malaysia P barbatum, it might seem reasonable to consider them conspecific. However, the extremes are readily distinguishable and whilst realizing the biological reality, it would undoubtedly cause considerable nomenclature confusion to reduce P. callosum into the synonymy of P. barbatum, or even treat it as a subspecies or variety of the later. Recognizing P callosum and P barbatum as specifically distinct is a compromise that is nomenclaturally and horticulturally satisfactory."

So the systematic characteristics probably are good for identifying the extremes in the two species, but not for splitting out the contiguous intergrades in the Malay peninsula.


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## gonewild (Jan 3, 2015)

So unless you know where they were collected you can't be sure what they are. In that case it probably makes no difference, just choose whichever name you like best.


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## Rick (Jan 3, 2015)

gonewild said:


> So unless you know where they were collected you can't be sure what they are. In that case it probably makes no difference, just choose whichever name you like best.



Exactly


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## tomkalina (Jan 3, 2015)

Wow! You guys have lost me on this one. Given the key, what floral morphology specific to barbatum do you see in this callosum?


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## gonewild (Jan 3, 2015)

tomkalina said:


> Wow! You guys have lost me on this one. Given the key, what floral morphology specific to barbatum do you see in this callosum?



See post #27.
It seems in this case floral morphology is not a sure way to determine genetics.


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## tomkalina (Jan 3, 2015)

Yes, unfortunately (along with Cribb's key) it's all we have.


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## Rick (Jan 3, 2015)

tomkalina said:


> Yes, unfortunately (along with Cribb's key) it's all we have.




The key is all messed up.

On page 337, Type description of P callosum var. sublaeve:

Dorsal sepal 3.4 - 4.2cm long and 3.0 - 4.1cm wide, shorter broader and less sigmoid petals (than nominal north Thai variety).

On page 330, Type description of P barbatum:
Dorsal sepal 3.9 - 5.0 cm long, 4.3 - 5.5cm wide.

His Type description of the North Thai P. callosum does have dorsal sepal dimensions going to 6cm. 

So if you have flowers from plants originating from the Malay peninsula then the smaller ones can just as easily be a callosum (var sublaeve) than a barbatum.

There are also light and dark barbatum so "darkness" is not characteristic of the species (although the darker forms are usually selected for).


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## tomkalina (Jan 3, 2015)

One wonders why he (Cribb), after taking all these things into consideration decided to separate them.....


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## Rick (Jan 3, 2015)

tomkalina said:


> One wonders why he (Cribb), after taking all these things into consideration decided to separate them.....



"it would undoubtedly cause considerable nomenclature confusion to reduce P. callosum into the synonymy of P. barbatum".

Sounds like he was trying to save us splitters from ourselves.


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## tomkalina (Jan 3, 2015)

A reasonable conclusion........ : )


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## Trithor (Jan 4, 2015)

So where does that leave us? :rollhappy:


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## gonewild (Jan 4, 2015)

Trithor said:


> So where does that leave us? :rollhappy:



With pretty flowers named Sue.


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