Geometric morphometric analysis of grain shape and the identification of two-rowed barley (Hordeum vulgare subsp distichum L.) in southern France

Jerome Ros*, Allowen Evin, Laurent Bouby, Marie-Pierre Ruas

*Corresponding author for this work

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43 Citations (Scopus)
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Hulled barley is one of the most frequently recovered cereals in European archaeological sites from Roman and medieval periods. In southern France this cereal is common in carbonized contexts such as cultural layers, ditches, pits, hearths, etc. The distinction between the two subspecies, two-rowed (Hordeum vulgare subsp. distichum L.) and six-rowed barley (H. vulgare subsp. vulgare L.) is usually based on morphological characters. The following criteria can be used to discriminate both subspecies from archaeological remains: the number of fertile spikelets per rachis segments, the linear or horseshoe shape depression of the lemma base, the maximum width of the caryopses and the proportion of twisted grains. The recovery of thousands of caryopses, some clearly twisted, and of rachis segments with sterile spikelets from the site of Petit Clos (Perpignan, Pyrenees-Orientales, France) dating to the Roman period suggests that both subspecies were cultivated during this time in southern Gaul. However evidence for two-rowed barley is usually scarce in archaeobotanical reports from Roman and medieval sites. To confirm the presence of two-rowed barley in the carbonized assemblage from Petit Clos and its cultivation, we developed a new method for analysing caryopses shape using geometric morphometrics with landmarks and sliding semi-landmarks. We compared modern reference specimens to the archaeological grains from several excavations from southern France dating from the 1st to the 11th century AD. Several varieties of both subspecies were correctly identified in the modern reference sample using GMM, both before and after carbonization. Archaeological specimens could then be accurately identified. The results confirm that both subspecies of barley were cultivated in southern France during the Roman period. (C) 2013 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)568-575
Number of pages8
JournalJournal of Archaeological Science
Publication statusPublished - Jan 2014

Bibliographical note

Open Access funded by Natural Environment Research Council
Under a Creative Commons license

We would like to thank Michel Lemoine (CNRS, Muséum), for his invaluable help during the carbonization of the fresh caryopses. We are also most grateful to the society Secobra for providing the fresh caryopses used in this study, to Raphaël Cornette (UMR7205) for welcoming us into the morphometric platform of the National Museum of Paris, to prof. Jean- Frédéric Terral (University Montpellier 2) for his advice and to Elizabeth Kerr (UMR7209) and Nelly Gidaszewski (UMR7205) for language editing. A. Evin acknowledges financial support from the Natural Environment Research Council, UK (grant number NE/F003382/1). Finally, we would like to thank the UMR7209 (CNRS-MNHN), for financial support.


  • archaeobotany
  • identification
  • experimental charring
  • agriculture
  • Roman period
  • Medieval period
  • cereal grains
  • historical biogeography
  • domestication
  • evolution


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