Grape variety is defined as ‘a single kind of grape. So Chardonnay is a variety, not a varietal,’ (Dr Ian D’Agata: 2014, p.x). See also monovarietal. Wine grapes come from the botanical genus Vitis which has more than 20 species of which the wine vine or Vitis vinifera is but one.
Dr Ian D’Agata, Native Wine Grapes of Italy (University of California Press, 2014), p.x.