Here is a perfect case of oenological homonymy: the term Vernaccia has been used to designate three native grapes (and their designations) that have nothing in common, except the name.
Vernaccia di San Giminiano is a white grapes variety with a very low diffusion. It is cultivated in the small town of San Giminiano, in Tuscany, and is at the base of the homonymous designation Vernaccia di San Giminiano DOGC.
Last but not least, Vernaccia di Oristano is a native white variety of Sardinia. Vinified in purity is at the base of Vernaccia di Oristano DOC.