RE: naming irises

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Naming species:

Sean Z. explanation below in his email on species naming basics and the number of iris species is excellent and on target. I have not followed closely the thread of Seanâs postings so I apologize if I repeat information previously posted. I am sure, everyone is well aware that there are lumpers and splitters among those who name species (irises as well as other plants and animals) and also that the information upon which a species description is based may subsequently be found to be deficient or inaccurate. But, ignoring that and assuming we have sufficient accurate data there is another problem. Different workers often use different concepts of what constitutes a species. For example, Coyne and Orr (2004) in their excellent book on speciation have an appendix that reviews a large number of species concepts. Other somewhat modern good texts on the subject are Avise (2002), Mayr (1942) and of course there is Grantâs 1981 book on plant speciation. Many, especially those with an ecological education and work background, including myself, prefer the biological species concept which Mayr (1995) defined as: âSpecies are groups of interbreeding natural populations that are reproductively isolated from other such groups.â Coyne and Orr (2004) adopt Mayrâs definition with a few caveats. They state that in their view ââdistinct species are characterized by substantial but not necessarily complete isolation.â And there is what Coyne and Orr term the âPhylogenetic Species Concepts (PSCs)â which is ââ concerned with identifying historically related groups of which systematics are the main proponents ââ Sometimes there can be quite a bit of acrimony between proponents of the two concepts. Often, the two groups come up with the same species delineations but sometimes they very hostilely disagree. I am especially interested in the distribution and status of wild Louisiana irises (i.e., I. hexagona, I. fulva, I. brevicaulis, I. giganticaerulea, and I. nelsonii). And, from what I can discern, I am coming more and more to the conclusion that I. hexagona and I. giganticaerulea are not distinct species. I am not alone in coming to that conclusion.ÂÂ

Vic

Avise, John C. 2002. Phylogeography The History and Formation of Species. Harvard University Press.

Coyne, Jerry A. and H. Allen Orr. 2004. Speciation. Sinauer Associates, Sunderland, Massachusetts, USA.

Grant, Vern. 1981. Plant Speciation. Columbia University Press, New York.

Mayr, E. 1942. Systematics and the Origin of Species. Columbia University Press.

Mayr, E. 1995. Species, Classification, and Evolution. pp. 3-12 in R. Arai, M. Kato, and Y. Doi (eds.) Biodiversity and Evolution. National Science Museum Foundation, Tokyo.