SCIENTIFIC COMMITTEE, SEPTEMBER 1. 



clxxiii 



curious "abnormal" form of G. lactifiora, " which comes in small percent- 

 age from the seed of the typical form, perhaps one in 200. The linear 

 leaves can be recognised early in the seedling stage, and I never saw 

 intermediate forms." Analogous forms with stellate flowers are not 

 uncommon in C. rotundifolia, and De Candolle in his monograph of 

 Campanula figures and describes one on G. Medium, which he considered 

 unique in the genus. 



Silver-leaf Disease in Apples and Plums. — Mr. Gaut brought speci- 

 mens from an orchard of 7 acres in Yorkshire. The soil is warp-land, 

 varying in depth from 1 to 3 feet within short distances, and overlying 

 clay. The drainage is good, with drain-pipes. Shelter is afforded by the 

 fruit-trees in the orchard. The altitude is nearly sea-level. The general 

 culture has been to give a good dressing of farmyard-manure every four 

 years, and lime every few years. The trees had been planted ten years, and 

 silver-leaf appeared three years ago, and is becoming worse every year. 

 The trees affected in summer die the following year. The varieties affected 

 are 1 Victoria ' Plums, of which there are about 500 trees, and ' Lord 

 Grosvenor ' Apple grafted on ' Keswick Codlin ' stock. The matter was 

 creating considerable interest in Yorkshire, and the soil had been analysed 

 with the following result : 



The air-dried soil contains in 100 parts — 



Water 3*10 per cent. 



Loss on ignition (organic matter, combined 



water, &c.) 5*09 „ 



Mineral matter 91 "81 „ 



100 00 



Containing nitrogen 0*151 per cent. 



Equal to ammonia 0-183 „ 



The soil ivas free from root fibres or any visible organic material. 



It had been said by some experts that silver-leaf was due to a lack of 

 nitrogen in the soil, but the analysis seemed to show this could hardly be 

 the cause (see correction on page clxxiv). 



Dr. Cooke, V.M.H., said that the disease was so mysterious because he 

 could find no spores or mycelium of fungus and no bacteria. He knew of 

 no remedy, but advised cutting out the parts affected the moment the 

 disease was seen and burning them. See Journ. R.H.S. vol. xxvii. pp. 

 713, cxliii, and cxlix. 



Rose-leaves diseased. — Mr. J. W. Scott sent three bundles of Rose- 

 leaves diseased.- "No. 1. The plants are in good health, and at present 

 there is but very little of the disease on them. No. 2 is taken from small 

 pot plants spring -grafted, which seem to develop these spots when grown 

 in a highly moist temperature. No. 3 appears to be like the last, attack- 

 ing plants that are in a soft-growth, and we have it in several houses, in 

 some cases stripping every leaf off the stem, but on taking the lights or 

 glass off, the plants recover to a great extent." 



Dr. Cooke pronounced the disease in each case to be Actinonema rosce, 



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