FUNGI AND FUNGOUS DISEASES OF PLANTS 243 



structures of the plant (fig. 188). Most of the damage is done 



to the fruit before any of these cups appear ; indeed, the fruit 



is worthless before the parasite has matured. Spores are dis- 



tributed from the cups and new infection of fruit occurs, and 



thus the destruction is continued. The spores are formed 



within the tissues of the cup in the enlarged ends of hyphae, 



and these enlarged spore-forming tips of the hyphse are the 



sacs from which the group name sac fungi is derived. The 



sac is called the ascus (sac), and the group of plants is called 



the Ascomycetes (sac fungi). 



Brown rot seems to attack 



all kinds of stone fruits, and 



the total amount of damage 



done by it is enormous. In 



1887 it was reported that 



the disease had caused a 



shortage of 800,000 baskets 



in the peach crop of Mary- 



land and Delaware for that 



year. In 1900 Georgia lost 



about 40 per cent of its peach 



crop a money loss of between 



$500,000 and $700,000.! 



The disease may be checked by destroying the infected fruits 

 and twigs. Spores are so generally distributed that spraying is 

 also necessary. Different sprays have been used, but with such 

 varying success that the advice of local experiment stations 

 should be sought for the special needs in each state. 



231. The morel. Another representative of the sac fungi 

 is the morel mushroom (Morchella) (fig. 189). Its mycelium 

 grows in earth that is very rich with decaying organic matter. 

 It is usually found in woods, among the leaves and about old 

 logs and stumps. The mushroom is the only part usually 

 noticed, and under favorable conditions of moisture and 



FIG. 189. A group of morel mushrooms 



i "The Brown Rot of Peaches, Plums, and Other Fruits," Bulletin SO, 

 Georgia Agr. Exp. Sta., 1900. 



