Vitis ×novae-angliae (Vitaceae): systematics, distribution and history of an “illegal” alien grape in Europe

Systematics and distribution in Europe of Vitis xnovae-angliae (= V. labrusca x V. riparia, Vitaceae), a naturalized North American neophyte introduced for wine production in the 19th century, are investigated. Original identification tools are provided and diagnostic characters are discussed in detail, with special reference to leaf, fruit and seed morphology and the flavour of ripe berries. The complex of events that led to its introduction and eventually to its prohibition in Europe are also taken into account. Original morphological data regarding infructescences and seeds of related taxa are also reported.