M. C. Loi, G. Marras & A. Maxia The flora of Monte Perda ‘e Liana (CE-Sardinia) Abstract Loi, M. C., Marras, G. & Maxia, A.: The flora of Monte Perda ‘e Liana, (CE-Sardinia). — Fl. Medit. 14: 153-172. 2004. — ISSN 1120-4052. This contribution presents the results of the floristic research carried out on Monte Perda ‘e Liana, one of the most characteristic Mesozoic calcareous formations of centre-eastern Sardinia. The found floristic component numbers 247 taxa that can be ascribed to 57 families and 176 genera. The endemic quota is made up of 44 species or 17.81% of the local flora most- ly ascribed to the Sardinian sector. The analysis of the biological forms has pointed out a high percentage of hemicryptophytes and therophytes; while the chorological spectrum has shown the dominance of steno and euri Mediterranean elements. Introduction Among the many geological forms that manifest themselves on the Sardinian territory, there is a vast group of mountains that characterises the centre-eastern area of the island and is ascribable chronologically to the Mesozoic Era. These reliefs are almost exclusive- ly represented by calcareous-dolomitic rocks at whose base are levels, a few metres deep, made up of granites or Palaeozoic schists. Though these outrcrops are separated today and as in the case of Perda ‘e Liana they occupy a limited territory, they testify to the existence in the past of a vast Mesozoic sea on this part of the island. An erosive process that lasted millions of years led to the for- mation of the typical isolated towers, named “Tacchi” o “Tonneri”. This erosion is still ongoing and often uncovers the underlying basement while modelling and further marking this landscape typology. The harsh morphology on the surface of the “Tacchi” shows that the limestones of which it is made have undergone deep changes due to karst phenomena, which manifest themselves with jagged edges and overhanging walls up to a few hundreds of metres tall. For a long time, these calcareous mountains were poorly known from a botanical point of view. The difficulty accessing the place as well as its insecurity have been the main obstacles to exploring its flora in a sufficiently analytical manner. It is only in the past cen- tury that the area has been visited by researchers (Morris 1858; Barbey 1884; Martelli 1896; Herzog 1909), who still did not draw up any large, detailed systematic lists. Thanks