Flora Delle Isole Palmaria e Tino (Golfo Della Spezia)

Abstract

Flora of Palmaria and Tino islands. — Palmaria and Tino are two small islands at the entrance of the Gulf of La Spezia. They are formed of grey fossiliferous limestones of the Rhaetian period and of more recent — but still of the Rhaetian period — dolomitic limestones. Their climate is definitely more mediterranean than that of the La Spezia coasts laying near by; the winters are milder and the annual precipitations much lower (at the Palmaria 525 mm, at La Spezia 1375 mm. The flora is composed of 399 entities and has a biological spectrum in which the Hemicryptophytes predominate (35,33%), however also the Therophytes (29,57%) and the Geophytes (15,03%) are frequent. The test of the floristic composition shows that the eumediterranean elements are predominant (24,56%) but also the submediterranean (12,53%) and the central southern European (13,53%) are frequent; besides, the subatlantic (6,01%) and the Eurasian ones are also to be found (9,27%). From the test of the floristic components of the three floras of Palmaria and Tino, Capo Caccia in north western Sardinia and of the Marettimo island in western Sicily, it has been found that there is a bigger quantity of eumediterranean elements than in the islands near La Spezia (24,56%) at Capo Caccia (42,14%) and at Marettimo (47,60%), and on the contrary a decrease of the central southern European (13,53%, 9,50%, 6,40%). The fact that the island of Sardinia was separated from the continent since very early times is proved by the presence at Capo Caccia of a lower number of euro-centralasiatic plants (6,76%, 3,30%, 6,60% respectively), of sub-Atlantic ones (6,01%, 1,65%, 3,80%), and of Eurasian ones (9,27%, 7,85%, 8,20%) and on the contrary by a higher number of Sardinian-Corsican endemisms at Capo Caccia (8,67%), definitely higher than the ones in Sicily at Marettimo (3,40%) and the Tuscan-Ligurian endemisms at Palmaria and Tino (only 0,75%) islands which are a few dozen meters near the coast, from which they were separated in recent periods. Among the plants of phytogeographycal interest I would like to mention Centaurea cineraria which is present at the Palmaria and Tino with the var. veneris; may be once spread on most of the Mediterranean coasts. Most of the Mediterranean plants growing on the Palmaria and Tino have a distribution area which includes a great part of the Mediterranean. Just a few of them (Cephalaria leucantha, Argyrolobium zanonii, Phagnalon sordidum, Staehelina dubia, Pinus pinaster, Antirrhinum latifolium) are western submediterranean, distributed mostly in Europe; in comparison, at Marettimo there are western eumediterranean plants growing in northern Africa with some remains in the Spanish peninsula. At Marettimo eastern eumediterranean plants also grow, while at Palmaria and Tino are to be found only some plants that, from the north-eastern coasts of the Mediterranean sea, reach the interior of the Balkan peninsula (Genista januensis) or the Pontic region. (Coronilla cretica, Dorycnium pentaphyllum var. berbaceum).