Abstract
To know plants utilized by prehistoric man, plant remains from archaeological sites should be identified. Plant remains found on house floors directly reflect plant usage of prehistoric people, but are mostly incinerized and carbonized. Identification of small carbonized cereals such as millet grains was very difficult, especially when only light microscopy was available. Gramineous plants including cereals accumulate silica in the epidermis, and their silica skeletons detected from their ash were found to have specific characteristics. The spodograms or Aschenbild were the only method of identification with light microscopy for ash or carbonized grains found on prehistoric house floors. When the scanning electron microscopy (SEM) began to be applied to the observation of carbonized remains, various kinds of useful plants other than Gramineae came to be identified, such as Perilla (Labiateae) and Brassica (Cruciferae). However, a limited number of researchers have tried identification of carbonized grains or detection of cereals from ash in Japan, probably because great efforts and time are needed for the collection and observation of extant comparative specimens.
