Quote: Eileen Whitehead Erlanson defining taxonomic inflation

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I was reading today to find the origin of the term “taxonomic inflation”. This is a common idea today from people who criticize an overzealous attention to defining species. The term “taxonomic inflation” is especially used by detractors of the phylogenetic species concept, on the logic that this species concept results in naming species from insufficient data.

In a discussion of species concepts, I wanted to provide this perspective and cite its origin, and I found that nobody who today uses the term ever cites its origin.

I found the earliest use of the term in a 1934 paper by the botanist Eileen Whitehead Erlanson. She uses it in a discussion of the problems of recognizing varieties below the species level:

The taxonomist must find some way of describing all the multitude of natural forms, and in Rosa the problem of how to treat the units smaller than a species is perplexing. GREGOR (23) pointed out that if a varietal name is appended to every specimen which differs in some minor point from the general description of the group, then "every genotype and every clonal modification of an individual would ultimately deserve varietal or sometimes specific rank." To name all the possible combinations of minor characteristics leads to such a state of taxonomic inflation that the categories below the genus lose all practical value. Nor can the morphological criteria alone be accepted as supplying a completely reliable system of classification (23), for morphologically similar forms may differ markedly physiologically, as has been found in R. acicglaris, R. woodsii Lindl., and R. arkansana Porter. Probably the most promising method for dealing with the smaller units is that of distinguishing minor variations by numbers or letters, which makes it possible to express dif- ferent character combinations clearly and succinctly without degrading scientific nomenclature. This has been advocated by VAVILOV (42), HALL and CLEMENTS (26), CLAUSEN (7), and HALL (25). It was recommended for the varieties of rose species by MATTHEWS (31) and is a method that I also would endorse.

The paper is “Experimental Data for a Revision of the North American Wild Roses” in the Botanical Gazette, which later became the International Journal of Plant Sciences.

The next person to use the term “taxonomic inflation” was the paleontologist William K. Gregory in a 1936 paper, On the Meaning and Limits of Irreversibility of Evolution”. I mention this because it is the only other early use of the term, but Gregory used it in a very different way that is not similar to the present usage of the term. Gregory was concerned that paleontologists were overzealous in their application of the idea that specializations cannot be reversed in evolution, and that this caused them to accept a much higher antiquity for some species lineages than they would if they could accept that specialized characters sometimes reverse to an ancestral state. Hence, the number of evolutionary lineages is “inflated” by the assumption that they must have separated before any specialized traits evolved.

The use of the term, taxonomic inflation, really took off in the 1960s after the president of the Linnaean Society of London, one T. M. Harris, devoted a speech to “The Inflation of Taxonomy”. This was a wholesale critique of oversplitting at every level of taxonomy, and was clearly influential upon later authors. However, as a speech, Harris seems to have felt no need to cite earlier authors. Nor did many later authors cite Harris’ work.

It seems that “taxonomic inflation” was an idea that many wanted to use, and few sought for the term’s source. I’m going to credit Erlanson.