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Plant Focus

Quercus macdougallii
A rare oak endemic to the Sierra Juárez in Oaxaca

Revisiting the Taxonomic and Nomenclatural Problems of the Quercus sinuata Walter Complex

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Ronald Lance

Published May 2022 in International Oaks No. 33: 27–44


The oak species generally known in the United States as “Durand oak” has been subject to multiple and discordant interpretations of its morphological, taxonomical, and  nomenclatural  significance. Its  nomenclature  is  a  particularly  contentious  issue and deserves a detailed explanation before further analyses of taxonomy are presented. This paper is a summary of the problems associated with recognition of Durand oak and an introduction to a research effort striving for remedial propositions. Throughout this article, the oaks of pertinence are most often referenced using their common colloquial names. The reason for frequent departure from specific epithets is for greater clarity: only one colloquial name is used for the oak of point, rather than one of the multiple epithets which are themselves a focus of nomenclatural dispute. The colloquial names used here are “Durand oak” (Quercus durandii, or Q. sinuata), “Bigelow oak” (Q. durandii var. breviloba, or Q. sinuata var. breviloba) and “bluff oak” (Q. austrina).

Three oak taxa are popularly considered representative of or allied to the Durand oak species complex (Photos 1-3). Taxonomic disagreement regarding the parameters of each taxon, whether deserving of specific, varietal, or synonymous status, has been ongoing since the beginning of the 19th  century. Across the Southern United States, from Central Texas eastward across the Gulf and Atlantic Coastal Plains to South Carolina, these three oaks have remained more distinctive in appearance than in nomenclatural clarity.


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