Vitis riparia
Vitis rupestris
frost grape, river grape, river-bank grape, vigne de rivages
rock grape, sand grape
bark exfoliating in shreds;
nodal diaphragms to 0.5 mm thick;
branchlets terete, glabrous or sparsely hirtellous, growing tips enveloped by unfolding leaves, glabrous or sparsely hairy;
tendrils along length of branchlets, persistent, branched, tendrils (or inflorescences) at only 2 consecutive nodes;
nodes not red-banded.
bark tardily exfoliating in plates;
nodal diaphragms to 1 mm thick;
branchlets terete, usually glabrous, sometimes sparsely hirtellous, growing tips enveloped by unfolding leaves;
tendrils absent or only at distalmost nodes, soon deciduous if not attached to support, branched, tendrils (or inflorescences) at only 2 consecutive nodes;
nodes not red-banded.
stipules 3–5 mm;
petiole 1/2 to ± equaling blade;
blade cordate, 6–20 cm, 3-shouldered to shallowly 3-lobed, apex short acuminate, abaxial surface not glaucous, glabrate, visible through hairs, veins and vein axils hirtellous, adaxial surface glabrous.
stipules 3–6.5 mm;
petiole 1/2 blade;
blade reniform, conduplicately folded, 5–10 cm, apex acute to short acuminate, usually 3-shouldered, rarely shallowly 3-lobed, abaxial surface not glaucous, usually glabrous, visible through hairs, veins and vein axils sometimes sparsely hirtellous, adaxial surface usually glabrous.
(4–)9–12 cm.
4–7 cm.
functionally unisexual.
functionally unisexual.
black, heavily glaucous, globose, 8–12 mm diam., skin separating from pulp;
lenticels absent.
black, slightly glaucous, globose, 8–12 mm diam., skin separating from pulp;
lenticels absent.
= 38.
= 38.
Vitis riparia
Vitis rupestris
Vitis riparia is native throughout much of its range. It has become naturalized in a few locations in Saskatchewan, Oregon, and Washington. Plants on dunes around the Great Lakes with hairier petioles and leaf blades sometimes have been recognized as var. syrticola; variation in hairiness is essentially continuous, however, and the form is not worthy of taxonomic recognition (P. M. Catling and G. Mitrow 2005).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Vitis rupestris once was widely scattered throughout most of its range, but now mostly is rare and may have been extirpated in many locations, apparently due to habitat loss. It is most common in the Ozark region of northern Arkansas and the southern half of Missouri, but is imperiled elsewhere (http://explorer.natureserve.org). It is persisting from cultivation in California and some other locations (J. Wen, pers. obs.; E. B. Wada and M. A. Walker, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=48433). Reports from Illinois were based on misidentifications (R. H. Mohlenbrock 2014). The species was used to develop many grape hybrids due to its resistance to disease (J. Gerrath et al. 2015)
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
OR, 
WA - Local Web sites:
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
LA Plants, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
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USDA Plants Database- LBJ Wildflower Center
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