Re: SPEC: I. kashmiriana

The following is for those who are interested in the species question.  If 
you are not technically-minded -- hit the DELETE key!

In a message dated 12/11/01 11:36:55 AM Mountain Standard Time, 
wshear@hsc.edu writes [quoting Clarence Mahan]:


> > Bill, you have a talent for jumping on topics of significance and 
> perplexity.
> > Nigel Service, who wrote the part of the BIS species book on Section Iris,
> > does indeed indicate 2n=44, 48. But I do not know for certain where the 
> 2n=48
> > comes from.  Both Simonet and Randolph reported 2n=44 (see the appendix to
> > "Garden Irises").   Service is the greatest authority on this iris, and by
> > reading what he has written, you can see that he leaves many unanswered
> > questions. 
> > 
> > I suspect that the 2n=48 comes from the fact that Randoph indicates that 
> I.
> > bartonii is 2n=48 "(indicated from progeny counts)".  If one assumes I.
> > bartonii is just a form of I. kashmiriana, and if one can rely on 
> chromosome
> > counts "indicated from progeny counts", I guess one could conclude that I.
> > kasmiriana sometimes has a count of 2n=48.  But, I would conclude that I.
> > bartonii and I. kashmiriana are not the same iris, and that the iris from 
> the
> > Vale of Kashmir has a chromosome count of 2n=44.
> 
It's been some time since we first discussed this on the list, and I don't 
think we posted the I. kashmiriana excerpts from Mitra's KARYOTYPE ANALYSIS 
OF BEARDED IRIS [BOTANICAL GAZETTE,Vol. 117, #4, June 1956], so here are a 
few quotes that may help newcomers understand the current discussion.

Of the source material:  "Specimen rhizomes from Kashmir, India, received 
through the courtesy of Mr. M.K. DUTT, seretary of the Agrihorticultural 
Society of India, Calcutta, India."

Of I. kashmiriana (2n=24)  "This is the first report of a 24-chromosome I. 
kashmiriana, which previously was represented only by 44- and 48-chromosome 
forms. The 12 chromosomes present in duplicate in the root tips of this 
24-chromosome I. kasmiriana are very similar to the 12 chromosomes present in 
quadruplicate in the somatic tissue of the tetraploid form of I. kashmiriana, 
to be described later, which from karyological analysis appears to be an 
autotetraploid."

I have not found the earlier report of a 48-chromosome form cited here, and 
from this message I conclude that Clarence hasn't found it either.  Mitra 
did, however, go on to provide a detailed report of the 48-chromosome form.

Of I. kashmiriana (2n=48)  "A careful study of the somatic chromosomes 
indicated that most of the chromosomes of the haploid complement of the 
24-chromosome race of I. kashmiriana are present in quadruplicate here."  
[Skipping the chromosome-by-chromosome analysis]  
"Since the karyotype of the diploid I. kashmiriana differs conspicuously with 
respect to several members of the complement from that of any other diploid 
tall bearded species which have been studied, it is improbable that any of 
the latter were involved in the parentage of the tetraploid I. kashmiriana.  
This, together with the fact that no other 24-chromosome tall bearded species 
has been reported from Kashmir, where both the diploid and the tetraploid 
forms of I. kashmiriana are endemic, is interpreted as evidence favoring the 
view that the tetrapoid originated by direct chromosome doubling of the 
diploid."

Mitra went far beyond chromosome counts, recording the characteristics of 
individual chromosomes and comparing patterns to assess evolutionary trends.  
To anyone interested in this level of detail, I strongly recommend obtaining 
a copy of the entire article -- but for most I think it is sufficient to 
report that the diploid form of I. kashmiriana was determined to be the most 
primitive karyotype of the study.  That should help explain why so many 
people of diverse interest find themselves seeking more information about I. 
kashmiriana.


My own take on the subject is that the Indian species need MUCH more study.  
Experts have counted I. kashmiriana as 2n=24, 2n=44, and 2n=48. Until proven 
otherwise, I chose to believe that all of these counts are valid -- based on 
variations in the specimens themselves: 

1.    The 2n=24 form was compared chromosome-by-chromosome with I. pallida 
with a finding of many similarities but far more differences.  It was 
compared with the tetraploid form of I. kashmiriana with a finding of many 
similarities and few differences.  "Splitters" would certainly have described 
it as a separate species.

2.    I don't have the detailed analysis of the 2n=44 count to compare with 
those of regelia species -- but find it most interesting that they share both 
a chromosome count and the unusual trait of hairs on the standards.  Again, 
"splitters" would undoubtedly have described this as a separate species.

3.    The 2n=48 form has been analyzed in detail, and has apparently been 
used to justify equating I. bartonii to I. kashmiriana. But "what if" the 
collected specimen described as I. bartonii was simply a 48-chromsome I. 
kashmiriana.....

This is getting far too long, so I'll just say that IF the Indian species had 
been subjected to the same amount of study as the European ones I suspect 
that "I. kashmiriana" would have been separated into at least three species 
-- but there are still many questions pending on this matter.


At this point, I should note that Mitra did not count I. bartonii -- and 
that, in itself, raises many questions in my mind.  Was this because no 
specimens of I. bartonii were available?  

Going back to Randolph's count based on progeny -- were descendants used 
because no authenticated specimens were available?  Had earlier assessments 
that I. bartonii was a synonym of I. kashmiriana already led to its 
assimilation?

More questions than answers, so let's go back to the beginning and work 
forward in time instead of just trying to explore backwards....


Baker [1892] presented I. bartonii & I. kashmiriana separately, noting the 
origin of the specimens.  

Dykes' [1913] classified the "Indian Pogoniris Group" by physical 
characteristics.  He remarked that "There seems no good reason for separating 
from I. kashmiriana Foster's I. bartoni."  He compared physical 
characteristics [including the rudimentary beard hairs on the standards that 
are a well-known distinguishing trait of I. kashmiriana], and the 
circumstances under which I. bartonii was collected [in a semi-cultivated 
state, consistent with what was then known of I. kashmiriana].


There are so many unanswered questions about I. bartonii and I. kashmiriana 
that I am still sitting firmly on the fence:  

1.    Accepting I. bartonii as a synonym of I. kashmiriana does provide 
closure -- but if that assessment is in error it also closes the very avenues 
of exploration that could prove or disprove its worth.

2.    Treating I. bartonii and I. kashmiriana as separate species keeps the 
question open -- and although it may ultimately prove to be wrong, it should 
at least lead to more complete answers than we have today.

So we come to the issue from very different viewpoints, but I must side with 
Clarence on this one!

Sharon McAllister


[Non-text portions of this message have been removed]


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