Background: While the utilitarian crops grown in vicarage gardens in pre-industrial Sweden have been fairly well documented, our knowledge of plants cultivated for food among the peasants and crofters is limited. Nevertheless, garden vegetables and herbs played a much more important role in the diet of the rural population from a nutritional point of view than, say, wild plants, at least in the southern part of the country. This study aims to explore the importance of edible cultivated onions, Allium, and their various cultivars and old landraces that were once—and in some cases still are—grown in home gardens. Methods: This study is based on documentation collected from national surveys carried out by the Swedish National Programme for Diversity of Cultivated Plants (POM), and from an intense search for references to the cultivation and use of carious onions in the historic garden literature, herbals and ethnographic records found in responses to folklife questionnaires. Results: The rural population in pre-industrial Sweden cultivated various kinds of bulb onions. They are known under various folk names, although their taxonomic affiliation has been unclear. Many folk taxa have been classified and named by their use, while other names refer to the practices associated with the cultivation system. These onions were often described as especially well suited for storage over winter. Onions have had a wide range of uses in Sweden. In some parts of Sweden, onions were eaten during church service in order to keep the churchgoers awake. Several types of onion have commonly been used as condiments in pickled herring dishes, spreads, sauces, foods made of blood and offal, dumplings, meat dishes and soups. Garlic was used for medicinal and magical purposes, as well as for ethnoveterinary medicine. Onion skins have traditionally been used for dyeing eggs at Easter. Conclusion: Genetic diversity of vegetables and garden crops represents a critical resource to achieve and maintain global food security. Therefore, ethnobiologists studying agricultural societies should place more focus on old landraces, cultivars and cultivation practices in order to understand the importance of garden crops for a society. They are an important element of sustainability.

Black elder, Sambucus nigra, is a non-native but now partly naturalized shrub in Sweden; it has been cultivated here at least since the Middle Ages. Previously, this plant was associated with a supernatural being to whom sacrifices were made, and its fruits were used in folk medicine and wood for fuel and crafts. Traditional economic uses vanished with industrialization and urbanization and black elder was mostly planted as an ornamental shrub in urban parks. At the end of the 1970s, however, it made a sudden comeback: city dwellers started to gather flowers to make a refreshing non-alcoholic cordial. This diachronic study of Sambucus nigra spanning over a millennium reflects various attitudes and uses within the context of a changing human society. In addition to the simple but popular cordial, side dishes and desserts made of its fragrant flowers are becoming increasingly popular in modern Swedish cuisine. Globally it has also been (re)discovered and the utilization of this plant is growing: its flowers are used to add flavor to soft drinks, salads, desserts and various dishes; berries are used for medicine and in cooking, especially with meats, and its future uses seem to be limited only by human imagination.

To deepen the knowledge of the plant material and the names use connected to cultons spread in the 19^th century might be of essential value. Historical records of old growing systems and propagation methods add valuable knowledge to the preservation values tied to the genetic diversity of the gene pool for future breeding. In historical records, different cultons, now regarded as Allium cepa L. has often been taxonomically divided into vegetatively propagated shallots and seed-propagated onions (Rabinowitch andKamenetsky 2002). Furthermore, shallots have been widely known by the rural population in Sweden as "potatislök" [potato onion] and preserved as heirloom landraces (Nygårds andLeino 2013; Strese andDe Vahl 2018). Differing practices and principles regarding distinguishing between potato onions, shallots and onions in European countries have sometimes made it difficult to understand historical records. This study presents the plant material of A. cepa L. Aggregatum Group introduced and spread in Sweden between 1830-1860. The plant material exemplifies different principles regarding the denominations and shows the range of cultons available in the north of Europe by the time, but also examples of domestic local cultivars. Shallot and potato onions, later mainly vegetatively propagated, were already in the 19^th century occasionally propagated and spread by true seed, in Europe and to Sweden. In addition, a Russian growing system with a true seed generation was known in literature.

This study presents the plant material of A. cepa L. Aggregatum-Group introduced and spread in Sweden between 1830 and 1860. The plant material exemplifies different principles regarding the denominations and shows the range of cultons available in the north of Europe by the time, but also examples of domestic local cultivars. It is essential to deepen the knowledge of the plant material and the name use connected to cultons spread in the nineteenth century. Historical records of old growing systems and propagation methods add valuable insights of the preservation values tied to the genetic diversity of the gene pool for future breeding. Differing practices and principles for distinguishing between potato onions, shallots and onions in European countries have sometimes made it difficult to understand historical records. The results of this study shows that shallot and potato onions, later mainly vegetatively propagated, were already in the nineteenth century occasionally propagated and spread by true seed in Europe. In addition, a Russian growing system with a true seed generation was found in literature. The article concludes that knowledge of older cultivation systems and introduction history deepens the link between the cultural-historical and the biological conservation values of plant material in long time preservation. Gene bank accessions may not only be valuable in breeding but also utilized and preserved as part of a biological or green heritage.