552 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



-sveather favourable, 80 per cent, may be relied on for succeeding. Weak 

 varieties may be grafted on vigorous stocks above the fourth or fifth bud. 

 Two to three hundred grafts can be inserted in one day on this method. 



Ti: C. W. 



Grafts, The Conditions of Success with {U.S.A. Exp. Stn. 

 Becord, vol xii. No. 10, 1901, p. 917). — A definition of terms used, and 

 the essential conditions for successfully uniting various families, genera, 

 and species of plants by grafting, are given. Two groups are arranged : — 

 (a) Physiological or true grafts, where the scion is entirely or partially 

 separated from its parent, and deprived cf the organs through which its 

 mineral foods in solution are obtained ; and the stock, partially or entirely 

 separated from its upper portion which possessed powers of absorbing 

 gaseous matter, and for elaboration of food material to form new tissues. 

 These are considered successful after fruit and seed have been formed. 

 {h) Anatomical, or grafts by approach, which are considered successful 

 w^hen the parts have thoroughly grown together so as to cause a wound 

 if divided. Grafts are dependent upon certain conditions for success, 

 namely : *' intrinsic," or relative botanical structure and nature, analogy, 

 and method of cicatrisation; and "extrinsic," conditions relating to 

 temperature, prevention of drying or decay of tissues, and manner in 

 which cut surfaces are held in conjunction. It was proved by experi- 

 ment that quite a number of cryptogamic and monocotyledonous plants 

 were capable of uniting their tissues, one of the most notable being 

 Selaginella arborca. The above, combined with other most useful and 

 interesting information, make these pages worthy of perusal by all those 

 interested in the subject of grafting. — E. F. H. 



Grape Diseases. By Newton B. Pierce {U.S.A. Dep. Agr. Farm. 

 Bull. XXX.). — The "Californian Vine Disease" is described as most deadly 

 and most obscure. It first appeared in 1884, since which time it has 

 destroyed 30,000 acres of vines. Small yellow spots first appear on the 

 leaf, and spread until a band of yellow is formed all down the tissue of 

 the leaf between the main veins. The centre of this band dies and turns 

 brown, and eventually the leaves fall and the canes turn black and die. 

 The next year the growth is weak and the same symptoms are repeated 

 in a more heightened form. The third year there may be no growth, or 

 so little that the summer sun kills it. At an earlv stage of the disease 

 the roots begin to show decay, the soft parts rotting and stripping from 

 the w^oody parts. 



At first the disease attacks onlv a \ine here and there, but it soon 

 spreads until the whole vineyard is destroyed. Cuttings of diseased vines 

 may strike well and make good early growth, but when the hot season 

 xjomes they at once begin to show disease. Cuttings procured from 

 Wealthy stock outside the disease area have not at present shown any sign 

 of infection. Like Peach Y^ellows and Silverleaf, the cause of the disease 

 is as yet unknown. 



"Powdery Mildew" is a fungoid disease too well known to all Grape 

 growers. It attacks all parts of the vine, but is specially destructive to 

 the bunches, causing the berries to split even w^hen it does not actually 

 destroy them.. In summer its conidia or spores make themselves very 



