THE ROOT SYSTEMS OF FRUIT PLANTS 587 



France, ignorance of local conditions and of the stocks suited to them may 

 indeed lead to utter failure. 



Other plants than the grape prove refractory on calcareous soils in 

 France and in many cases recourse to a lime resistant stock has proved 

 successful. DentaP^ furnishes an instance in the Australian Acacia 

 dealbata which grows freely in calcareous soils on A . floribunda though on 

 its own roots it will not grow in such soils. A similar expedient is neces- 

 sary for the growth of certain pines in these soils. Some Australian exper- 

 ience seems to indicate that sour orange is the best stock for orange and 

 lemon in sections where the irrigation water is likely to contain alkali 

 in considerable quantities. '^^ California experience indicates that lemon 

 is unusually susceptible to alkali.^'' On the other hand, lemon roots are 

 stated to be the best foragers in poor soils in this section. Primus davi- 

 diana is now under trial in Cahfornia as an almond stock; the particular 

 quality commending it is its ability to grow in more alkaline soils than 

 other commonly used almond stocks.^*- Two successive plantings of 

 peaches in one California orchard were killed by alkali; following this 

 peaches on Davidiana roots have proved successful in the same soil.^^' 

 Cock^^ states that the trifoliate orange, though it is too dwarfing in its 

 effects to be a commercial success, may be used to advantage in very wet 

 soils. In the Gulf States the trifoliate succeeds in rich, moist soils and is 

 unsuited to light, dry soil.^^^ Pomelo in California appears to suffer 

 most from drought.-*^ Sahut^^'^ states that in wet soils the peach and 

 apricot grow better on plum roots than on their own or on almond roots 

 and that the cherry on Mahaleb grows in poor soils where it would not 

 grow on its own roots. 



The degree of refinement to which adaptation of stocks can be carried is shown 

 by Bioletti's tentative recommendations of stocks for Vinifera grapes in Cali- 

 fornia :-^ 



"The Rupestris St. George has given its best results in the hot, dry interior on 

 deep soils. . . . 



"For a great majority of our soils and varieties the two Riparia X Rupestris 

 hybrids 3306 and 3309 promise to be superior in every way to the St. George. 

 The former for the moister soils and the latter for the drier. . . . 



"For the wettest locations in which vines are planted — in places where the 

 water stands for many weeks during the winter, or where the bottom water rises 

 too near the surface during the summer— the most promising stock is Solonis X 

 Riparia 1616. 



"For moist, rich, deep, well-drained soils, especially in the coast counties and 

 on northerly slopes, the St. George is utterly unsuited. The crops on this stock, 

 in such locations, are apt to be small, and the sugar content of the grapes defec- 

 tive. In these locations the Riparia Gloire is much to be preferred, and will 

 undoubtedly give larger crops of better ripened grapes. 



"None of the above stocks give good results, as a rule, in very compact soils. 



