Should Bromus secalinus (rye brome) be considered a crop?: Analysis of Bromus rich assemblages from protohistoric and historic sites in northern France and textual references

Several hundred archaeobotanical studies now provide a broad overview of plant husbandry practices in northern France from the Bronze Age to the medieval period. Some unknowns nevertheless remain concerning the species considered as possible minor crops. They often have an ambiguous status, which deserves a closer examination in order to specify their possible cultivation and uses. This is the case of Bromus secalinus (rye brome), a wild member of the Poaceae, which was potentially used as food and fodder, and whose consumption has been suggested by several authors based on the regular discovery of mass finds of its seeds in domestic contexts and assemblages including cultivated plants. Rye brome has then been considered as a "near-crop". Could the re-examination of brome grass rich assemblages and processed crops of cereal grains help us to clarify the status of the plant? On the basis of the macrofossil results from 338 occupations in northern France dated from 1325 BC to AD 1500 and the comparison of archaeological finds with ancient texts, we try to discover what the uses of this plant may have been and how its perception may have evolved over time. The discovery of possible seed cake fragments made of brome grass in two rural settlements represents a hint for its potential consumption during the Iron Age. However a careful examination of the frequencies of rye brome over the time span shows that abundant finds are ultimately rather few and mainly clustered before the 2nd century BC, when a major change in crop choices happened. This led to a change in the processing of cereals and the form in which they were brought back to the sites. Abundant rye brome finds appear to be linked to the persistence of hulled cereals and the processing techniques that were specifically applied to them.