264 . PLANT DISEASES 



Aeddium esculentum, Barcl. The young shoots of Acacia 

 eburnea are, in India, distorted and rendered succulent 

 by the action of this fungus, and such are used as food. 



Aeddium ornamentale, Kalchbr. This aecidium some- 

 times appears in enormous numbers on branches and 

 spines of Acacia horrida, at the Cape of Good Hope. The 

 entire structure and general appearance is completely 

 altered, the branches forming fantastic curves. 



Peridermium harknessi, M.OQ?e.=P.Jilatnentosum, Peck. 

 The following account accompanied specimens of this 

 fungus, sent to Kew by Dr. Harkness, from Sacramente, 

 California : 



' Fungus found growing upon Pinus ponderosa, Dougl., 

 up the Sierra Nevada mountains. It attacks the young 

 tree trunks, and arrests further growth.' 



In all the specimens I have had an opportunity of 

 examining, the fungus has first attacked the stem when 

 two or three years of age, and in one instance had con- 

 tinued to grow year by year until the tree was thirteen 

 years of age, when the specimen had been collected. 

 During this period of growth, the fungus had caused the 

 stem at the point of attack to assume a barrel shape, four 

 inches long, and three inches in diameter. The stem just 

 below the swelling was one and a half inches across. 



The fungus also attacks the following North American 

 trees : Pinus insignis, Dougl., P. sabiniana^ Dougl., 

 P. contort a, Dougl. 



Peridermium pint, Wallr. A well-known parasite, 

 attacking various pines in Europe and the United States. 

 The mycelium is perennial in the bark, bast, and wood, 

 and continues to extend year by year. As a rule the 

 cambium is not destroyed all round the branch at one 



