SCIENTIFIC COMMITTEE, DECEMBER 17. 



ccxxiii 



deep canals ; but no results have as yet been obtained. In Java the 

 planters cut out the Coffee-trees infected by Tylenchus, and avoid 

 planting Coffee again on the same ground for several years. In Egypt 

 this disease should be carefully watched, as the Tylenchus might perhaps 

 attack other plants — for instance, th^ newly cultivated Sugar-Beet." 

 (See also a Report on this subject, p. 844.) 



Violet Disease. — Referring to former communications on this subject 

 (see p. 491), Mr. Hutton, of Donaghadee, writes : — 



" I wish to bring another point to your notice, i.e., the question of 

 infection being carried through the a^r, and not being dependent upon 

 contact alone. That this is the case will, I think, be shown by the fact 

 that fresh and healthy plants which I procured from Surrey early in 

 September, and which were planted in fresh ground at least a hundred 

 yards distant from any affected plants, showed signs of the ' spot ' very 

 shortly afterwards, and in about two months were completely destroyed. 

 Every care was taken to isolate these plants during unpacking and other 

 stages. It would be of importance to know the experience of other 

 growers who have had annoyance from this disease, and whether in any 

 case the culture of Violets has been successfully renewed, and if so, what 

 length of time was allowed to pass before recommencing it. I am 

 of opinion that, when once the fungus has appeared or become esta- 

 blished, any attempt at replanting fresh stock will be useless, unless all 

 former plants are destroyed and a certain length of time allowed to 

 elapse, in order to ' starve out ' any germs which might be located in 

 places other than the soil itself, and whose presence would cause a return 

 of the trouble. If the vitality of the spores under different conditions 

 could be determined, the result might prove of assistance to any grower 

 who, as in my case, may have had a total loss of crop, but is desirous of 

 commencing agq,in, if this could be done with safety." 



Diseased Peach-shoots. — Mr. Gordon showed some Peach-shoots in 

 which isolated patches on the outer bark were dead. He suggested that 

 the appearances were the result of the attack of the Shot-hole fungus 

 Cercospora. The specimens were referred to Mr. Massee for examination 

 and report. 



Seedless Grapes. — Mr. Gordon also showed specimens of Grapes devoid 

 of seed. This was attributed to imperfect fertilisation. Some varieties, 

 it was remarked, are much more liable to imperfect fertilisation than 

 others, and a difference is observable according as the Grapes are grafted 

 on a particular stock, or are on their own roots. 



Zanthoxylum alatum. — Mr. Odell showed specimens of this tree, 

 remarking that " the specimen shown is from a large shrub growing at 

 ' The Grove,' Stanmore, Middlesex, where it annually develops its fruits 

 and seed. It is a native of N. India, Nepaul, Khasia, and China, the 

 fruits and seed being used by the Chinese both as a drug and a condiment, 

 and known as ' Hwa-tseaon.' A full account is given by the late Mr. D. 

 Hanbury in Science Papers ('Notes on Chinese Materia Medica '). Mr. 

 Hanbury also read a paper before the Linnean Society in 1863 on a case of 

 presumed parthenogenesis in Zanthoxylum alatum {Science Papers, p. 818). 

 The flowers of the specimen brought are apetalous and appear to be 

 polygamous ; but, although seed is produced in abundance, not one has 



