An inventory and analysis of the food plants of southern Africa

The food plants of southern Africa have not yet been been systematically recorded and the main patterns of plant use have therefore never been studied. The book by Fox and Norwood Young (1982) entitled “Food from the Veld” has been the most comprehensive to date and has become the standard reference work on the subject. However, this publication has become outdated and it is evident that many species were not included. We present here, for the first time, a comprehensive inventory and checklist of the edible plants of southern Africa, i.e., the Flora of Southern Africa (FSA) region. Seventy-four literature sources, including books, journal articles, checklists, grey literature and published ethnobotanical surveys were used to compile the inventory, which includes 1740 species (more than double the number listed by Fox and Norwood Young). All edible plants were marked-off in an Excel spreadsheet of all southern African plant species, made available by the South African National Biodiversity Institute (SANBI). Using the Excel format, it was possible to easily explore the main patterns relating to the frequency of citation of the species, the number of species at different taxonomic ranks (families, genera and species), the plant parts that are used and the use categories within the region. For a selection of 13 indigenous cultural/language groups (for which adequate information was available), we quantified the local preferences (for the most species-rich families, the most commonly used plant parts and the most frequent categories of use. The food plant data for southern Africa were also compared to sub-Saharan Africa and the entire world. Surprisingly, it was found that the Apocynaceae was the most species-rich family of southern Africa food plants, with a total of 137 species, followed by the Fabaceae (135 species), Asteraceae (94 species) and Poaceae (73 species). A similar pattern was found in sub-Saharan Africa, but with Fabaceae in the first position, followed by Apocynaceae. The family-level pattern for the entire world is different, where the Apocynaceae is unimportant, being replaced by Rosaceae (the last-mentioned is of very low significance in Africa). The most species-rich food plant genus in southern Africa is Searsia, while Solanum nigrum and Sclerocarya birrea have the highest frequency of citation in the literature. The most popular plant part used as a food in southern Africa, as well as in the entire world, are fruits, followed by leaves and then underground storage organs. The most species-rich category of food plant use is those consumed raw (and mostly in situ) as snacks, followed by those which are cooked as vegetables. The Apocynaceae have mostly edible underground storage organs as the edible parts, while Fabaceae is more diverse. Fruits and leaves have been determined as the most important plant parts used as food for most of the cultural groups except for the Khoekhoe group, where underground parts are the most important. For all of the cultural groups, plants used for snacks were the most important. A chronological list of publications shows that there were seven major contributions since the first survey by Van der Stel in 1685. The comprehensive inventory provides profound new insights into foraging and human food ecology and may also have value in interpreting and reconstructing the availability of food plants during the evolution of early humans in southern Africa.