314 MANUAL OF AMERICAN GRAPE-GROWING 



and others. In France, these varieties have given particularly 

 good results on bare, rocky soils with hot, dry exposures. In 

 California, Rupestris does not flourish in dry locations, and as 

 it suckers profusely and does not take the graft as readily as 

 Vulpina and ^Estivalis, it is not largely propagated. 



The clusters of fruit are small, with berries about the size 

 of a currant and varying from sweet to sour. The berry is 

 characterized by much pigment under the skin. The fruit 

 has a sprightly taste wholly free from any disagreeable foxiness. 

 Rupestris under cultivation is said to be very resistant to rot 

 and mildew of the foliage. The vine is considered hardy in 

 the Southwest. The attention of hybridizers was attracted 

 to this species over thirty years ago, and various hybrids have 

 been produced of great promise for grape-breeding. The root 

 system of Rupestris is peculiar in that the roots penetrate at 

 once deeply into the ground instead of extending laterally as 

 in other species. Like those of Vulpina, the roots are slender, 

 hard and resistant to phylloxera. The species is easily propa- 

 gated by cuttings. The vines bench-graft readily but are 

 difficult to handle in field grafting. 



4. Vitis wlpina, Linn. (V. riparia, Michx.). Winter 

 Grape. River Grape. Riverside Grape. Riverbank Grape. 

 Sweet-scented Grape. 



Vine very vigorous, climbing. Shoots cylindrical or angled, usually 

 smooth, slender ; diaphragms thin ; tendrils intermittent, slender, 

 usually bifid. Leaves with large stipules ; leaf-blade large, thin, 

 entire, three- or lower ones often five-lobed ; sinuses shallow, angular ; 

 petiolar sinus broad, usually shallow; margin with incised, sharply 

 serrate teeth of variable size; light green, glabrous above, glabrous 

 but sometimes pubescent on ribs and veins below. Cluster small, 

 compact, shouldered ; peduncle short. Berries small, black with a 

 heavy blue bloom. Seeds two to four, small, notched, short, plump, 

 with very short beak ; chalaza narrowly oval, depressed, indistinct ; 

 raphe usually a groove, sometimes distinct. Very variable in flavor 

 and time of ripening. 



