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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



which is nearly globose, except at their junction, where they are flattened, 

 the lower cell being a little the smaller. The cell coat is chestnut brown 

 and thickly covered with rather rigid obtuse spines (30-45 x 17-25 

 At first the short uncoloured pedicels are distinct, but these finally dis- 

 appear. 



Known in Europe, North America, India, Cape Colony, Australia, and 

 Tasmania. 



McAlpine Fung. Dis. 23 ; Journ. B.H.S. xxvi. (1902), p. 963 ; Sacc. 

 SyU. vii. ; Plowr. Br. Ured. 193 ; Mass. PL Dis. 251, fig. 64 ; Cooke Hdbk. 

 No. 1511 ; Cooke M.F. 211 ; Tubeuf, Dis. 355. 



Plum Pockets. 

 Exoascus pruni (Fckl.), PI. XI. fig. 13. 



Berkeley recognised this disease in 1876. The pockets, or " bladder 

 Plums," appear soon after the fall of the flowers, attaining full size about 

 the end of June, and then soon falling from the tree. They are at first 

 nearly globose, soon becoming elongated, and often somewhat curved, 

 from one to two inches in length, and a half to one inch in diameter. 

 They much resemble the proper fruit when young, except in being 

 yellowish or reddish in colour. With age the colour changes to grey, and 

 the surface looks mealy or frosted, and wrinkled. Ultimately they turn 

 nearly black, and in two or three days fall to the ground. The walls of 

 the bladders are thick, permeated by mycelium, which also enters the 

 hollow centre, and there is no stone. The fruits are evidently taken 

 possession of by the fungus at an early stage, seed production arrested, 

 and hollow bladders produced, which have some resemblance only to 

 fruit. 



The mycelium is of the usual kind, and may be found in the smaller 

 branches in early spring before the diseased fruit appears. The fungus 

 itself consists of small cylinders, or asci, standing side by side, closely 

 packed, each cylinder containing eight small globose sporidia, which are 

 ultimately ejected at the ruptured apex (4 // diam.). 



The sporidia germinate readily in water by the formation of a bud, 

 which assumes the form of the parent spore. The secondary spore 

 produces a bud like the first, and so on, through several generations. 



It is recommended to remove the "pockets" as soon as they are 

 formed. In the United States it is the practice to cut back the branches 

 bo as to destroy all parts likely to contain mycelium. 



Sacc. Syll. viii. 3842; Mass. PL Dis. 85, fig. 12; Ward, Dis. PL 

 p. 107 : Tim m. Pom. p. 8H ; Tubeuf, Dis. p. 155, fig. 



lYlM-I.KAl BLOTCH. 



Pohjst'ujma rubra (Pers.), PI. XI. fig. 14. 



These blotches are very rare upon the leaves of the cultivated Plum, 

 but are common enough on those of the Sloe. 



The blotches are orbicular or angular, of a brick-red colour, with 

 a decisive and definite outline, thicker than the leaf, with a waxy 

 appearance, and when mature dotted over the surface with darker minute 



