DISEASES OF CITRUS TRIES ] 63 



the spores proceed forth to propagate mischief. The 

 fungus destroys the branch or trunk upon which it 

 grows, but death may be delayed for four or five years, 

 each year the sporocarp increasing in size. The fungous 

 outgrowth should be removed and burned: the dead 

 wood harbouring the mycelium should be cut off, the 

 wound washed with a 5 per cent, solution of sulphate 

 of copper, and thickly painted with tar. But if the 

 fungus attacks a branch and not the trunk, it is safer 

 to remove that branch and burn it, painting with tar 

 the resulting wound. Polyporus fu mosus, Pers., is much 

 rarer, and can be combated in the same manner. 



Agaricus Citri which is not known to exist in these 

 Islands, and Agaricus Hesperidum are two saprophytic 

 mushrooms which thrive on the rotten roots of Citrus 

 trees, which have been separated from the tree 

 during careless tillage, or which have been killed 

 by gummosis of the roots (mal della cagna). Some 

 writers consider these fungi as capable of real parasitism 

 on living roots. Anyhow, it is advisable to gather and 

 burn them as soon as they appear above the ground, 

 before the formation of spores. Agavicus Citri grows in 

 clusters ; the stipes or stalk may be white, yellow or 

 reddish, about 5 c.m. in height. The pileus or cap is of 

 the size of a crown or a little larger, having a waxy white 

 margin, the rest being yellowish half hidden under a 

 mealy powder. Agaricus Hesperidum has the same habit 

 as the preceding. Its stipes is 7 or 8 c.m. in height, 

 white and hollow. Its membraneous waxy cap may reach 

 4 c.m. in diameter. They are more or less similar to 

 Agaricus me Ileus, Quel (Ar mil I aria mellea, Vahl) already 

 referred to, which is a much more deadly species. 



A small fungus often met with in vast clusters at the 

 base of the trunk is Psathynella disseminata, Quel, with 

 caps hardly exceeding i c.m. in diameter. This species is 

 purely saprophytic, living on the dead mosses and organic 

 detritus at the base of the trunk, but is quite harmless, 



