l8 AMERICAN VINES. 



do not grow under the same conditions. In America it grows 

 in the beds of dry ravines, in the midst of stones mixed with 

 very little organic soil. The Riparia is more particular. 

 The Vialla, Lenoir, Herbemont, and especially V. Monticola, 

 grow fairly well in poor soil. 



Such are the principal conditions which influence the 

 growth of the vine in slightly or non-calcareous soils. These 

 conditions may be easily modified. Lightness, and conse- 

 quently permeability of the soil, are necessary to a good 

 growth of the vine; deep trenching, green manure, long 

 manure (stable refuse with much straw), attentuate con- 

 siderably the compactness of soil. Drainage and trans- 

 ference also diminish the excess of water and coldness in 

 damp soils. On the contrary, in too dry soils irrigation when 

 possible, with frequent ploughing, will maintain sufficient 

 moisture. Finally, strong manuring will supply any de- 

 ficiency in the fertility of the soil. 



A good growth of all American vines can be assured after 

 this in all classes of soils, but it is none the less necessary 

 to take their preferences into account. 



B. CALCAREOUS SOILS. 

 Chlorosis 



In calcareous soils, as already shown, both American and 

 European vines, but the latter to a less extent, often become 

 yellow. Sometimes the yellow colour is only slightly marked 

 and transitory; again, on the contrary, it is more accentuated 

 and causes the death of the vine. In most cases it is a 

 characteristic symptom of the non-adaptation of the vine to 

 such soils. 



(a) Characteristic Symptoms of Chlorosis. The intensity 

 of the colour of leaves on vines attacked by chlorosis at 

 first diminishes over the whole parenchyma, or on portions of 

 it only. They then turn yellowish -green, and finally yellow. 

 The leaf loses almost all colour, and from bright yellow turns 

 to whitish. The tissue becomes brownish on the margin of 

 the limb, and this modification gradually invades the whole 

 parenchyma, following the ribs. Finally the whole leaf 

 dries up The young shoots become yellow in the same 



