Plants as Affected by Fungous Parasites. 183 



For the treatment of barley seed for the prevention 

 of smut use one pint of formalin in twenty gallons of 

 water. 



326. Fungi that develop from Spores Surviving 

 the Winter In or Upon the Soil, as the onion* smut, 

 cannot be prevented by disinfecting the seed. For this 

 disease a mixture of flowers of sulfur and air-slaked 

 lime, sown with the seed, has proved beneficial by pre- 

 venting infection of the young plant. 



327. Fungi the Spores of which Survive the Winter 

 Within their Dead-Host Plants, as in the club-root of 



Fig. 77. Apple affected with 

 scab (the dark spots), Fuslcladlum 

 dendriticum. (After Scribner.) 



Fig. 78. A scab spot magni- 

 fied. (After Trelease.) 



'■!fyf&^g^< 



Fig. 79. Section through a 

 scab spot, highly magnified. 

 The egg-shaped parts at the 

 right are the spores. (After 

 Trelease.) 



the cabbage* and turnip, and the onion mildew,! may 

 be held in check to some extent by burning the fungus- 

 killed plants at the close of the season. 



* Improperly called a fungous. In reality a slime mold. 

 phera Brasslcae. f Peronctpora Sctileideniana. 



Plasmidn- 



