CHOICE OF AMBKICAN VINES. 55 



favour, and they may sometimes result in grave failures. It 

 is only in cases where vines of pure American origin cannot 

 adapt themselves to the soil that the above hybrids may be 

 used, but these circumstances seem to be very exceptional, 

 and, in a general way, we may say that we possess pure 

 American graft-bearers for all varieties of soils where the 

 vine is generally cultivated, as we will show in the study of 

 adaptation to soil. 



2nd. ADAPTATION TO SOIL. 



"With a few exceptions, the species of American vines 

 growing in the United States do not thrive in limestone soils, 

 especially if the limestone is in an easily assimilable form. 

 They become more or less yellow when there is a small pro- 

 portion of this substance, and die if there is a large percentage 

 of it. Sometimes chlorosis brings about complete discolora- 

 tion, and even the destruction of the parenchyma of the leaf, 

 prevents the cane from lignifying, the vine becoming stunted 

 and dying if the evil lasts several consecutive years. The 

 reconstitution of vineyards on limestone soils has been one of 

 the greatest difficulties vine-growers had to contend with ; 

 therefore an exact knowledge of the quantity of limestone 

 different American grafc-bearers can stand is of very great 

 importance with regard to the study of adaptation to soil. 



At the beginning of this question the percentage of car- 

 bonate of lime contained in soils where American vines grew 

 well or became chlorosed was simply measured, and after the 

 mission of P. Viala, in America, in 1887, B. Chauzit gave, 

 in 1889, the following table, showing from personal analysis, 

 the percentage of linie which different American vines could 

 stand : * 



Percentage of Carbonate of Lime ! American Vines Growing Well. 



Less than 10 per cent. ... Most American Vines. 

 From 10 to 20 per cent. ... Riparia, Taylor, Vialla. 



From 20 to 30 per cent Jacquez, Rupestris, Solonis. 



From 30 to 40 per cent. . . . Champin, Othello. 

 From 40 to 50 per cent. ... V. Monticola. 

 Over 60 per cent. ... V. Berlamlieri. 



* B. Chauzit : Etude nut- l\i.aij.,tati(>ii au wl dts dynes Aim'ricuinris, in Utie Mission en 

 Amtrique, by Pierre Viala. Montpellier, 1889. 



