Southern Switurland is a mountainous region in which chestnut is cultivated since nearly 2000 years. Like other mountain regions of the mediterranean area, chestnuts had a foundamental importance as food supply of men. Attention was paid to a large differentiation of the product, i.e. different pomologic characteristics of the fruits: 94 different chestnut varieties names are known in Southern Switurland. In order to better discriminate among clones and varieties, and to certify the identity of many unknown or uncertain clones, it is intended to inventory the still existing varieties and to register both, genetical (see part II and III) and morphological characters. In our study 51 varieties have been identified until now. 6 varieties do not seem to exist any more. Varieties show characteristic geographic patterns of distribution: overregional, regional, or just local distribution. Some  varieties (5) can be differentiated by phenotypic characters, others are very difficult to distinguish, even  through fruit examination. Thus, genetic inventories are required to overcome problems in the phenotypic  distinction between varieties and in detection of different local denominations of one and the same variety.