Vitis riparia
Vitis aestivalis
frost grape, river grape, river-bank grape, vigne de rivages
summer grape, summer or post oak or big summer or silverleaf or blue grape, vigne d'été
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 exfoliating in shreds;
nodal diaphragms 1–4 mm thick;
branchlets terete, tomentose, arachnoid-floccose, or glabrous, growing tips not enveloped by unfolding leaves;
tendrils along length of branchlets, persistent, 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 1–4 mm;
petiole ± equaling blade;
blade cordate to orbiculate, 7–25 cm, unlobed to 3-shouldered or 3–5-lobed, sometimes deeply so, apex acute to short acuminate, abaxial surface glaucous, ± arachnoid or floccose, visible through hairs, hairs usually rusty, sometimes whitish, veins and vein axils sometimes hirtellous, adaxial surface glabrous or puberulent.
(4–)9–12 cm.
7–20 cm.
functionally unisexual.
functionally unisexual.
black, heavily glaucous, globose, 8–12 mm diam., skin separating from pulp;
lenticels absent.
black, glaucous, globose, 8–20 mm diam., skin separating from pulp;
lenticels absent.
= 38.
= 38.
Vitis riparia
Vitis aestivalis
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 aestivalis is sometimes confused with V. cinerea. However, the glaucous abaxial leaf surfaces, more heavily glaucous and larger berries, terete branchlets that are less evenly pubescent, preference for better drained, drier habitats, and earlier blooming period distinguish V. aestivalis from V. cinerea.
Several varieties have been recognized based on leaf and young stem pubescence and fruit sizes (B. L. Comeaux et al. 1987; M. O. Moore 1991). The boundaries of the varieties are highly inconsistent and it is often difficult to apply the varietal concepts in the field. Recent molecular evidence supports the monophyly of V. aestivalis, but none of the varieties were supported as monophyletic (Wan Y. et al. 2013).
(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
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Encyclopedia of Life
- Wikipedia
- Google Image Search
