Contribution to the knowledge of the therophytic flora of Sardinia

The abundance of therophytes, largely contributes to the naturalistic value of Sardinia. Moreover, most of the annual species belonging to the Sardinian flora have an historical and cultural value, as they followed the men in his migrations and still reflect the different ways of traditional land exploitation characterising the island. As a matter of fact, the development of human technology increased number and frequency of the annual plants of Sardinia. Nowadays, annuals occur in several habitats of the island, where they play a primary ecological role, both as biomass producers and protecting the soil from rill erosion during the rainy season, at least where the environmental factors do not let a thick layer of perennial plants. In the frame of a research about the ephemeral flora and vegetation of Sardinia, an updated checklist of the annual plant occurring on the island will be presented. The list is based on the available bibliography, integrated with data collected in the field. Synthetic diagrams dealing with chorology, growth form, dispersal strategies, blooming period and anthesic colour of the Sardinian annual plants will be related both to the Italian flora and to the following phytosociological classes: Tuberarietea guttatae, Saginetea maritimae, Cakiletea maritimae, Thero-Suaedetea, Isoeto-Nanojuncetea, Polygono arenastri-Poetea annuae, Stellarietea mediae.