This seems to be correct in regard to species and hybrids de- 

 veloped by nature in the southern States of the East, but does not 

 hold good with all vines of a sluggish growth, selected by French 

 experimenters, as the Berlandieri hybrids. Neither would such 

 vines be hardy enough that they could occur wild in regions where 

 Riparia, Rupestris and Berlandieri exist or even in intermediate 

 regions. The great difference between root and top of sluggish 

 growers as explained, is undoubtedly the reason why they do not 

 grow from cuttings. The facility of difficulty with which a vine 

 girows from cuttings, indicates therefore the extent of the differ- 

 ence between its root and top in regard to sensitiveness to tem- 

 perature conditions. 



It is probably not entirely accurate to use the two terms free 

 and sluggish growers, as the latter in their native home have about 

 the same growth habit as free growers have in the northern States. 

 But in using these two terms, the effect, which is the most im- 

 portant in this connection, is pointed out more than the cause. 

 The greater sensitiveness to coldness in the soil of the root of a 

 sluggislr grower in comparison with with that of its top, serves 

 as a check to prevent it from exhausting its vitality in a region 

 which must be extremely favorable for a rank and vigorous 

 growth of the grape vine and so to save it from becoming a prey 

 to parasitic organisms. On the other hand the free-growing 

 Riparias and pure Rupestris, not easily affected by certain low 

 temperature conditions in the soil, ajre enabled through this to 

 thrive in the more northern States, where cold springs and short 

 summers prevail. Rupestris really occurs further south, but it 

 is enabled to succeed there, I believe, more on account of its 

 drouth-resistant' leaf and other qualities, which disappear after 

 grafting. 



In most Viniferas and the" Californica we have a growth habit, 

 quite distinct from that of Riparia and Rupestris and also Candi- 

 cans and other sluggish growers, in that they start growth rather 

 late during spring and then grow very vigorously. The reason for 

 this is very likely, that at that time temperature conditions become 

 extremely favorable for root and top simultaneously. Growth 

 habit is the most variable characteristic of the grape vine, but 

 the least variation in this respect may be productive of the greatest 

 hardiness or the greatest weakness. 



