1180 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Pollination, Orchard. By F. Martin Duncan (Gard. Mag. No. 

 2532, p. 291, 10 5/1902). — In this article on an important matter the 

 writer discusses the causes of unfruitfulness among orchard trees, whether 

 due to frost, rain, wind, or other causes. The writer has evidently made 

 a minute study of the subject, as he records his observations in a clear 

 way. If the causes of sterility in orchards can be obviated by simple 

 means, such as the selection of varieties and the carrying out of other 

 details, such as soil and site for an orchard, then the matter is of the 

 utmost importance to the fruit grower. 



There are, however, other causes of unfruitfulness in orchard trees 

 which are beyond the control of cultivation. — W. G. 



Polygonum polystaehyum, Wallich. By P. Hariot (Le Jard. 

 Jan. 5, 1902, p. 4). — An article recommending and describing this little- 

 known Himalayan ' Knot-weed,' which bears long spikes of white flowers in 

 late autumn, and, being very hardy, is suitable for rough rocky wildernesses 

 where little cultivation is required. It is less encroaching and more 

 ornamental than P. cuspidatum, and half the height. — C. W. D. 



Potato Cultivation (U.S.A. Exp. Stn. New Jersey, Ann. Beport, 

 Oct. 1901, pp. 388, 389). — A mulch of two inches of wood shaving in 

 July on land planted with Potatos gave an increased yield over that on 

 unmulched land in the proportion of 360 : 310 ; there was also less scab 

 on the mulched portion. — F. J. C. 



Potato Disease, A new. By M. C. Potter (Jour. Bd. Agr. vol. ix. 

 No. 3, 1902, pp. 320-323, pi. iv).— This fungoid disease is attributed to 

 Chrysojjhlyctis endobiotica of Schilberszky.* It produces large, irregu- 

 lar, convoluted, tumour-like swellings on the potato- tuber. " Judging 

 from some sections in an early stage, the attack appears to commence at 

 the 1 eyes,' the parasite easily gaining an entrance into the outer cells of 

 the young and tender structures which normally would develop into 

 leaves. In these the cells are readily stimulated to divide, and, as a 

 result of the injury caused by the parasitic invasion, irregular cell-division 

 is set up. The destruction of any one cell causes those in contact with 

 it to divide in the attempt to heal the wound ; when these latter cells are 

 attacked in their turn, a further cell-division is induced, and by a repeti- 

 tion of the process the leaf-protuberances become converted into an irregular 

 cell-mass which in the initial stages may be seen as finger-like out- 

 growths. From these points the irritation spreads along the cork- 

 cambium, so that the cells over a large portion of the surface of the 

 Potato gradually undergo this irregular division and multiplication, 

 which is extended also into the internal tissues." 



The disease has been reported only from Cheshire.+ — B. N. 



Potato Diseases, Some. Anon. (Jowrn. Bd. Agr. vol. ix. No. 3, 



1902, pp. 307-311, pis. i-iii.). — i. Black Scab (QtJdomyces leproides, 



* M Ein neuer Schorfparasit der KartoiTelknollen." Bcrichte d. Dcut. Bot. Gesell. 

 Bd. xiv., 1H%. 



f Many examples of potato-tubers infected with this curious fungoid disease were 

 sent to me in VMY2 from several localities in Cheshire. - R. N. 



