246 MANUAL OF MODEKN VITICULTUHE. 



the vine grows older, as we have found by the examination 

 of three-year-old Rupestris St. George vines, secondary roots 

 are sent out in a direction more approaching the Ijorizontal. 

 These utilize the upper layers of soil, but as they constitute 

 but a small part of the whole root system and injury to them 

 is not severely felt by the vine. 



An injury to the lower roots, however, is more injurious 

 to the Rupestris. This explains the unsuitableness of this 

 species for badly-drained soils, and for soils where the water 

 level is high for a long time in winter and spring, and espe- 

 cially for those irrigated districts where the water level rises 

 during the growing period of spring and summer. The 

 standing water causes the root hairs on the main part of the 

 root system to decay, and deprived thus of its only means 

 of obtaining water the Rupestris dies of drought as truly 

 as does the Riparia when the main part of its rootlets and 

 root hairs are destroyed by the heat and dryness of summer. 



The strong sturdy growth of the Rupestris du Lot, 

 as compared with the comparatively slender growth of what 

 seems to be the best of the Riparias, is also well shown by- 

 the figures. This makes the Rupestris du Lot particu- 

 larly valuable as a stock for our heav}^-growing varieties of 

 Yinifera. This heavy growth of the grafts on Rupestris 

 .du Lot has been fonnd in France to have a tendency to make 

 them bear poorly and " go to wood." This, however, may 

 be considered a good fault, as it is easily counteracted by 

 more generous pruning, by leaving a larger number of buds, 

 and thus by diverting the whole vigour of the vine into a 

 larger number of shoots, decreasing the vigour of each and 

 increasing their fertility. Some grape-growers, especially in 

 the South of France, report enormous crops on vines grafted 

 on Rupestris St. George. 



Following are descriptions of the three varieties of resis- 

 tant stock which at present give the most promise of being 

 adapted to California. The leaves of the three varieties are 

 shown on the title page. 



Riparia Gloire de Montpellier. (Synonyms Riparia 

 Portalis, Riparia Michel, Riparia Saporta.) This is one of 

 the most vigorous of all the varieties of Riparia, and is 

 equalled only by the Riparia Grand Glabre and the Scrib- 

 ner Riparia. The stem or trunk is thick ; canes spreading, 

 long, with elongated internodes of medium thickness, 

 slightly bent at the nodes (giving the canes a faint zigzag 



