756 



Journal of Agriculture 



[lo Dec, 1910. 



As the result of their investigations, in the course of which they 

 examined a large number of different vines, Degrully and Ravaz arrived 

 at the conclusions given below. Though a good deal of difference exists 

 between different varieties, and even between individual vines of the same 



I. ROOT SYSTEM OF RUPESTRIS DU LOT. 



variety, in a general way the l)ulk of the roots of a vine tend to group 

 themselves at a uniform depth, and that this is not far from the surface. 



In all the species of vines which we have studied — 



1. Roots originating near the surface make at first an acute angle with the 



vertical. They tend to plunge. 



2. Roots originating more deeply, at a level varying according to the cultiva- 



tion of the soil, are directed at right angles with the vertical. They 

 spread horizontally. 



3. Roots originating still more deeply make an obtuse angle, with the vertical. 



They tend to rise, describing a curve which is the reverse of that 

 formed near the surface. 



4. All roots establish themscl\es, after a time, at the same level, which is 



no doubt variable . . . but which is fairly close to the surface. 



5. From these principal and mainly horizontal roots [tracantes] spring, at 



intervals, other roots {racines flongeantes) which plunge into the deepest 

 parts of the soil. 



From a comparison of Figs, i and 2 it is evident that the root system 

 of Rupestris du Lot, in which plunging roots are largely represented, is 

 far better able to resist drought than that of Vitia Riparia with its hori- 

 zontal roots. This is abundantly borne out by what actually happens, and, 

 as every one knows, V. Riparia has proved an unsuitable stock in any but 

 deep, moist soils. So much for the influence of variety. But vines of 



\ 



S. ROOT SYSTEM OF V. RIPARIA (l8 YEARS OLD). 



the same variety, grown in different soils, will not behave alike. Unless 

 the plunging roots found a subsoil into which they could penetrate, it 

 would not be possible for the roots to establi.sh themselves as in Fig. 2. 

 Deep preparation is the most powerful factor in facilitating penetration ; 



