Starch granules can often be identified to family, and in some cases to genus. Not all starch can be identified to this level because there are significant overlaps in size and shape between some species. Numerous identification keys have been developed for starches, but these are often difficult to apply to archaeological residues that commonly consist of a ‘soup’ of material recovered from a stone surface. Starch granule identification is most likely when ethnographic evidence indicates a limited list of possible species, and/or where accessory plant material such as tissue remnants, phytoliths (see Phytolith Analysis), and raph-ides (calcium oxalate crystals) are also present.
Comparative Reference Collections
Modern comparative reference collections are an essential component of starch research. A comprehensive reference collection of economic and noneconomic starch-producing species obtained from the study area can provide a clear indication of the expected types that may occur in the archaeological sample. Because relevant economic species vary from place to place, comparative reference material needs to be compiled on a regional basis. Species lists for a particular area are mainly compiled from local informants, ethnographic accounts, and botanical surveys. A detailed description of these assemblages is the important first step to identifying starch to family or genus. Consultation with botanists and their collections is important for obtaining advice on collection techniques, herbarium preparation (including voucher specimens), and for compiling reference collections that include multiple specimens of each species. Variation in starch grain size is known to occur with changing environmental conditions, and the magnitude of this variability must be assessed among all reference taxa before archaeological assemblages can be effectively assessed.
World History
