16. Vitis cinerea (Engelmann) Millardet, Mém. Soc. Sci. Phys. Nat. Bordeaux, sér. 2. 3: 319, 336. 1880.
Downy or sweet winter or graybark grape, parra silvestre Downy or sweet winter or graybark grape, parra silvestre
Vitis aestivalis Michaux var. cinerea Engelmann in A. Gray, Manual ed. 5, 676. 1867
Plants high climbing, sparsely branched. Branches: bark exfoliating in shreds; nodal diaphragms 1.5–3.5 mm thick; branchlets slightly to distinctly angled, densely hirtellous and/or sparsely to densely arachnoid, to glabrate, growing tips not enveloped by unfolding leaves; tendrils along length of branchlets, persistent, branched, tendrils (or inflorescences) at only 2 consecutive nodes; nodes sometimes red-banded. Leaves: stipules 1–3 mm; petiole ± equaling blade; blade cordate, 6–20 cm, usually unlobed to 3-shouldered, sometimes 3-lobed, apex acute to acuminate, abaxial surface not glaucous, sparsely to densely arachnoid or glabrous, visible through hairs, veins and vein axils hirtellous, adaxial surface glabrous or hairy. Inflorescences 10–25 cm. Flowers functionally unisexual. Berries black, slightly or not glaucous, globose, 4–8 mm diam., skin separating from pulp, lenticels absent.
Varieties 5 (4 in the flora): c, e United States, ne Mexico.
Vitis cinerea var. tomentosa (Planchon) Comeaux is endemic to northeastern Mexico (B. L. Comeaux and J. Lu 2000).
Vitis cinerea is sometimes confused with V. aestivalis; see the discussion under that species. Vitis cinerea as defined here is highly variable and is in need of field studies and phylogeographic analysis, along with its tropical relatives V. biforma Rose and V. tiliifolia. Wan Y. et al. (2013) concluded that V. cinerea is not monophyletic.