Vitis x Koberi (Vitaceae) alle Isole Tremiti

The genus Vitis L. (Vitaceae Juss.) includes about 50 species. However, since the high morphological variability, and the hybridization, there is a disagreement among the botanists, and the number of the taxa ranges from 35 to 65. Moreover, the grapes were domesticated by humans (hundreds of cultivars) related to their remarkable importance from cultural and economic point of view. The European flora includes 9 taxa in the genus Vitis (hybrids are included) of which only 1 (V. vinifera L.) is authoctonous, the other ones mostly native to America (Lumbreras, 2003; Ardenghi et al., 2013). Concerning Italy, 7 taxa are currently recorded [V. lambrusca L., V. riparia Michx., V. rupestris Scheele, V. vinifera, and the hybrids V. × instabilis Ardenghi, Galasso, Banfi and Lastrucci (V. riparia Michx. × V. rupestris Scheele), V. × koberi Ardenghi, Galasso, Banfi and Lastrucci (V. berlandieri Planch. × V. riparia) e V. ruggerii Ardenghi, Galasso, Banfi and Lastrucci (V. berlandieri × V. rupestris)], of which 3 (V. vinifera, V. × instabilis e × V. koberi), all considered exotics] occur in Apulia (south-east Italy) (see Ardenghi et al., 2013). During the field surveys in the Tremiti archipelagos, a population of Vitis × koberi was discovered (island San Domino), representing the first record for the archipelag, and the second record for the Apulia. The population colonizes a large area (about 11,000 m2), mainly uncultivated lands and mediterranean shrub. Furthermore, some individuals were found along ditches, associated with Equisetum ramosissimus Desf., so showing a wide ecological demand. The hybrid can be considered naturalized in San Domino, mainly spreading by vegetative reproduction. On the basis of the observations in field, V. koberi causes threats on the native vegetation by reducing the available area, and the natural resources. From the morphological point of view, this hybrids shows intermediate characters between the parents (V. berlandieri Planchon, and V. riparia Michx.) especially in the leaves features (length of the blade, hairness, basal sinus shape, and teeths of the blade). We hope for at least a monitoring of the population found. Since V. × koberi shows an high reproduction capability, this species is potentially invasive with damages to the natural vegetation. Therefore, actions for the eradication should be consider.