The Marche, in central Italy on the Adriatic, is the home of verdicchio (verdicchio bianco), cultivated principally here where it is generally made into simple, clean white wines.
In the top sites and at low yields, however, verdicchio can make a racy, bold, crisp wine with far more personality. (The same grape is used in the Veneto, alongside garganega, to make the best Soaves, where it is confusingly called trebbiano di Soave.)
The Wine Bible (2nd ed.) does not give the Marche its own regional chapter, so this context is drawn from its verdicchio glossary entry rather than a fuller regional treatment.