Underground Storage Organs (USOs) commonly known as roots, tubers or bulbs and also referred to as parenchymatous tissue, are plant structures that store energy (mostly carbohydrates) and water. Current research suggests that USOs had a key role in two capital moments of human history: as a fall-back and also staple food during hominin evolution; and at the beginning of the domestication of plants and animals in south-west Asia, where USOs may be as important as cereals and legumes. Therefore, it can be expected that they had a major role in plenty of other hunter-gatherer prehistoric societies but have been to date undervalued for multiple reasons such as retrieval issues, identification difficulties and also the focus on other food resources. The result is that these materials remain very often unstudied, kept in drawers without further analysis, together with other materials such as bread-like and food remains. All these reasons, together with the limited availability of atlases and reference collections available, explain the underrepresentation of this resource in the archaeological record.

CHUFA aims to stablish a systematic methodology for USOs creating a digital reference collection database and developing experimental archaeology. The main objectives of this proposal are: a) Application of new methods to study parenchymatous tissue remains (ESEM, 3Dscanner and microCT), b) Creation and publication of a botanical reference collection of USOs using the new methods and c) Creation of a data base on use-wear traces and residues on experimental material related to USOs labour. Through its interdisciplinary approach this project will provide archaeobotanists and use-wear analysis specialists with reference material for the identification of USOs and their processing in archaeological sites and fill in this gap in hunter-gatherer investigation.​