Re: 'Swerti' spelling


 

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For those interested in these issues . . . . ( pallida / variegata )
 
See "Breeding Red Irises" self published by Dr. Dan Meckenstock in his chapter "Related Genetic Systems". This is an excellent treatment of anthocyanin and carotinoid floral pigment developmental pathways in iris. Critical published citations are included. The significance of pigment pathways in iris is particularly relevant to discussion of species origin and history, such as the pallida / variegata topic mentioned in the post below. Further, the independent genetic systems of plicata and glaciata modifiy these pigment expressions. See page 88 for a clearly presented argument for parallel derivation of pallida and variegata from a common ancestral population. I happen to agree with Dr. Meckenstock on this conclusion though he certainly does not need my opinion to support his well documented conclusion.
 
Let me jump off here to personal conclusions regarding plicata. Since the plicata genetic system is an indicator of "jumping gene" activity, ( or a transposable element in technical jargon = TE ), the following might be noted regarding plicata inheritance. This is personal opinion and should not be attributed to Dr. Meckenstock as I do not know him except through his book. If this last proves to be in error, the error is mine. Plicata modifies pigment _expression_ present in iris flowers. It is almost certainly native to numerous iris species and clades as it is expressed in the universal plant language of DNA. TE's frequently function with two independent elements present on different chromosomes. ( yes, we know there are type 1 and type 2 TE's, but lets stay on the general point ) This alone means that normal crossing over cannot be assumed and simple Mendelian inheritance should not be expected to fit observed progenies. The _expression_ of TE's can turn independent genes on and off. They can rearrange gene sequences on chromosomes by insertion / deletion / duplication. This type of genetic variation by its very nature, is not entirely predictable. TE's are well known to be latent for periods of time only to reappear. In summary, plicata _expression_ alone is not likely to be a reliable marker with which to unravel the historical genetic tapestry of pallida/variegata. Naturally, the _expression_ of TE's in some iris backgrounds may be more frequent than others. Additional ties of TE's with retro-viruses and other non-genetic factors is strongly suspected and more recently becoming documented. Maybe this is jumpin' to conclusions, but I have questions about plicata as a useful ancestral marker.
 
None of this blunts my enthusiasm for a good plicata that grows well in the Northeast !
 
irisman646
 
 
 
----- Original Message -----
From: i*@aim.com
To: i*@yahoogroups.com
Sent: Wednesday, October 26, 2011 12:23 AM
Subject: RE: [iris-species] 'Swerti' spelling

 

Bozena Mitic, botanist with University of Zagreb in Croatia has studied pallida and related species very, very intensively over several decades. He has also had many, many other people collecting  pallida and related species for him over full range of its distribution. No reports of anything remotely like  what we know of as cultivar "Iris sweertii" no reports of any wild location. just  in gardens where most likely were pallida and variagata collected species. One study had over 400 cultivars collected from numerous different locations. He has published many papers. I have copies of ten of these papers.

I had also made test cross of Iris pallida kupari with  regular Iris pallida.  Seedlings were just a variation on a theme of bicolours and pallida blues. Over 50 seedlings in this cross. I also made cross of "Iris sweeertii" with I. pallida. No plicatas in these seedlings either. I'll have to include these crosses in the paper as well.

If plicata genes were  in Iris pallida it would have shown up much before now, and definitely should have reveled themselves in these test crosses.

What is showing is  a result of combining genetics of  I. variagata  with genes of I. pallida.

Plicata  pattern  isn't a single trait. It is a combination of genes. My other research shows this definitely. The particular traits are still being pinned down, but I'm fairly sure of what  they are but not of all the details and implications. But this info is being kept under hat pending further research.  A slow reveal. This paper on the species cross is the first reveal. (actually the second one. The first  is a bit sneaky as I didn't mention plicata). Too much new info to do it in one go.

Chuck Chapman




-----Original Message-----
From: David Ferguson <manzano57@msn.com>
To: iris-species <iris-species@yahoogroups.com>
Sent: Tue, Oct 25, 2011 10:40 pm
Subject: RE: [iris-species] 'Swerti' spelling

 

This is an interesting discussion. 

A few comments.  
First, as to the proper spelling of the name, as a botanical species, subspecies, or varietal name it would be "swertii".  Ignoring gender (this thing was named after an individual man, so we'll ignore the alternatives) the standard in botany is that if the name ends in a "hard" consonant, the ending is "ii", regardless of how it was originally published.  If the name ends in a vowel or a "soft" consonant (such as y or r), there is one "i" added at the end.  The name "swertii" was described as a botanical species name, so this is the proper spelling when used in this way.
Next, expounding a bit on what Robert said,  the name "swertii" is generally considered (by botanists) to be a synonym of Iris pallida based on a flower color form.  A botanical usage of a name applies to all plants that belong to the original population the name was described from (and the color of the flowers is totally irrelevant - if it varies within the population).  So, since "I. swertii" is a younger name, and not a different species - only a form - it is listed as a junior synonym.  If the name "swertii" were the oldest species name (the name of priority) for what we now call "I. pallida", everything in the wild species population would be called "I. swertii", regardless of  size, color, or whatever might vary within the population; however, "pallida" is older, so we call them all "Iris pallida".  Similarly, if "swertii" were the oldest name for a subpopulation (subspecies or variety) of I. pallida, it would be the proper name for that group of plants (apparently it has no such priority, so again it is listed as a synonym of the one it is supposed to belong to).
However, when used as a horticultural "cultivar name", the name need not follow any botanical rules - but there are various rules for cultivar names that various organizations have set forth.  The use of a botanical name for a cultivar is almost always discouraged - it just causes confusion - yet there are quite a few very old Iris cultivars bearing names of what were originally described as botanical species.  When used in this way, these names apply only to the one one "clone" (all individuals bearing the name are propagules from the same original plant; or, in another word a "cultivar").  In theory these old cultivars are supposed to be the actual original plant that the species name was described from, but in most instances is it highly likely that they are not.  Regardless, the cultivar versions of the names should not be confused with the original botanical usages of the names.  The Iris that is most often called Iris pallida cv. 'Swerti', may or may not be the original plant described as Iris swertii, but it doesn't matter - in practice they are two totally different and separate usages of the name.  The cultivar need not even really belong to the biological population that originally bore the botanical name.  It can get very very very confusing unless one remembers that the two usages are not the same.  As for the spelling of the cultivar name 'Swerti', the argument has been (to my understanding)  - ? - that since it was originally (in the AIS registry / checklist ??) spelled with one "i" (was it?), that is the proper spelling.  I don't have a preference, and to me it's not important - I'm a botanist, and I'm a bit biased.  A cultivar is an individual plant in a garden, and it has little to do with wild populations in nature and with the study of botany (unless that plant is of known provenance, in which case it is just one of many representatives of a wild species).  When a name is used for a cultivar, it is different than when used as a botanical designation.
As for the hybrid origin of 'Swerti' and other plicata "I. pallida", I'm not yet convinced one way or the other.  The documented man-made hybrids I've seen (including the ones Chuck posted) do not look the same as plants like 'Swerti' and 'Plicata', and clearly show their I. variegata ancestry (although, the second one is getting about as close as I've seen so far).  I would suggest that if I. variegata really is the source of the plicata genes, it is most likely through past hybridization and backcrossing with wild I. pallida, and that the genes are incorporated into wild populations of I. pallida - where somebody found and collected an odd-ball plant that was named "Iris swertii".  Realistically, the early date of collection of the Iris called 'Swerti' would imply to me that it was more likely to have occurred in nature, and not by chance in some garden.  It could have happened in gardens too, but it just seems an unlikely scenario - to me.  It would be nice to know - for a fact - if plicatas occur among wild I. pallida or not.  There is so little botanical information available regarding wild Iris species (even most European ones) that it is very hard to get a real picture of what is found in the wild.  Most available information regarding the genus Iris is based on and biased through limited horticultural plant collecting, which tends to focus on attention-grabbing individual plants instead of on populations as a whole.  Variation tends to be ignored as a part of whole populations, and given way too much significance on an individual plant basis.  Descriptions in books (especially those devoted to the genus) usually do not allow for variation, but just parrot the original descriptions and characteristics known garden plants of a given species.  As one example, in the books, Iris pallida is supposed to include only plants with white spathes, but the species is clearly varied in this trait, and they can be brown or anything between white and brown.  Flowers are supposed to be blue-violet, but they can clearly vary to more reddish purple hues, and to white.  However, the basic morphology seems quite constant.
Of course, I would love the opportunity to study them extensively in the wild, but I'm based too far away for it to likely ever be practical for me to do so.  So, I grow a few in gardens, and have to "settle".
Dave FergusonRio Grande Botanic GardenAlbuquerque



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