Segetal flora of Italy

The concept of “weed” is very subjective, as any plant that interferes with human activities can be considered a weed. Almost exclusively annual, weeds of arable land are called “agrestals” or “segetals” and were negatively affected, in Europe, by the intensification of agriculture. In recent years, many studies highlighted the ecological and agronomic benefits of these species in agricultural systems. In climates with a cold season, segetal plants can be divided in two main groups according to their phenology, following the one of the cultivated species: taxa of winter crops, like winter wheat, and taxa of summer crops, like maize. Segetal species of winter crops are mostly native or archaeophyte in Europe, and often strong specialist of their habitat. They also include several anecophytes, “homeless weeds” that evolved in the last 10,000 years under agricultural conditions and do not have a natural habitat. Weed species are selected and evolve according to their ability to mimic crop attributes as lifecycle and ecology and, then, to survive agricultural practices. Many segetal plants are crop wild relatives and consequently a potential source of genes to improve the features of crop species. Thus, the segetal flora of winter cereal crops is particularly valuable from a conservation and evolutionary perspective. This dataset contributed to provide the first inventory of the segetal flora of Italian winter cereal crops and allied crop types, including flax and autumn-sown legumes (Fanfarillo et al. 2020). The entire database consists of over 30,000 records, derived from different sources: phytosociological and floristic relevés, local and regional floras, single floristic notes and, subordinately, herbarium samples. Here, we publish 24,676 occurrence data deriving from 1,240 relevés.