Vitis riparia
Vitaceae
frost grape, river grape, river-bank grape, vigne de rivages
grape family
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.
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.
alternate, simple or palmately or pinnately compound;
stipules present;
petiole present;
blade often palmately lobed, margins dentate, serrate, or crenate;
venation palmate or pinnate.
(4–)9–12 cm.
bisexual or functionally unisexual, axillary or terminal and appearing leaf-opposed, cymes or thryses [spikes].
functionally unisexual.
bisexual or unisexual;
perianth and androecium hypogynous;
hypanthium absent;
sepals 4–5(–9), connate most or all of length;
petals (3–)4–5(–9), distinct (connate distally, forming calyptra, in Vitis) [connate basally], valvate, free;
nectary intrastaminal;
stamens (3–)4–5(–9), opposite petals, distinct;
anthers dehiscing by longitudinal slits;
staminodes present in functionally pistillate flowers;
pistil 1, 2[–3]-carpellate, ovary superior, 2[–3]-locular, placentation axile, sometimes appearing parietal;
ovules 2 per locule, apotropous or anatropous;
style 1;
stigma 1 [4].
berries.
black, heavily glaucous, globose, 8–12 mm diam., skin separating from pulp;
lenticels absent.
1–4 per fruit.
or lianas, occasionally shrubby [trees], synoecious, dioecious, or polygamomonoecious; commonly with multicellular, stalked, caducous, spheric structures (pearl glands);
tendrils usually present, rarely absent.
= 38.
Vitis riparia
Vitaceae
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.)
Genera 15, species ca. 900 (6 genera, 30 species in the flora).
In the past decade, considerable effort has been made to reconstruct the phylogeny of Vitaceae (M. Rossetto et al. 2001, 2002; M. J. Ingrouille et al. 2002; A. Soejima and Wen J. 2006; Wen et al. 2007; Ren H. et al. 2011; A. Trias-Blasi et al. 2012; Lu L. M. et al. 2013; Wen et al. 2013b; Zhang N. et al. 2015). These analyses have generally supported five major clades within Vitaceae: the Ampelopsis clade, the Ampelocissus-Vitis clade, the Parthenocissus-Yua clade, the core Cissus clade, and the Cayratia-Cyphostemma-Tetrastigma clade.
Placentation type and ovary locule number in Vitaceae have been interpreted in different ways. Most authors state that the gynoecium is bilocular and the placentation type is axile (for example, J. E. Planchon 1887; P. K. Endress 2010), but others report the gynoecium as unilocular and refer to the placentation type as parietal (V. Puri 1952; N. C. Nair and K. V. Mani 1960). Recent anatomical studies confirm that the ovary in Vitaceae is usually bilocular [occasionally trilocular in Cayratia, or unilocular in some species of Cyphostemma (Planchon) Alston, such as Cyphostemma sandersonii (Harvey) Descoings], and that the placentation is axile, although it may sometimes appear parietal (S. M. Ickert-Bond et al. 2014).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves 2–3-pinnately compound. | Nekemias |
1. Leaves simple or palmately compound. | → 2 |
2. Pith brown; petals connate distally, forming calyptra; bark exfoliating (adherent in Vitis rotundifolia). | Vitis |
2. Pith white; petals distinct; bark adherent. | → 3 |
3. Petals 4; stamens 4. | → 4 |
4. Inflorescences leaf-opposed; seeds 1(–4) per fruit. | Cissus |
4. Inflorescences axillary; seeds 2–4 per fruit. | Causonis |
3. Petals 5; stamens 5. | → 5 |
5. Tendrils 2-branched; nectaries cup-shaped, adnate proximally to base of ovary, free distally; styles elongate, cylindric. | Ampelopsis |
5. Tendrils 3–12-branched; nectaries annular, adnate to base of ovary, or absent; styles short, conic. | Parthenocissus |
- 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
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras:
CA, OR - Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
