[Vol. 2 



430 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



with Prof. Delacroix in Paris (Nov. 28, 1901) and from an 

 examination of material furnished by him I learned that it is 

 not uncommon throughout France on the potato. It will be 

 recalled that the perfect stage was described by Prillieux and 

 Delacroix ('91). Judging from the amount of the black 

 speck disease observed on the potato in the markets of various 

 cities in southern Europe during 1905- '06 the writer would 

 infer that it is of more frequent occurrence than is reported. 

 Pethybridge ('11) finds the fungus (including the Corticium 

 stage) well distributed in Ireland, and it is reported from 

 other parts of Great Britain. 



McAlpine ( '11) has reported this fungus on the potato from 

 several points in Australia, and he states that it occurs upon a 

 variety of economic plants. Since it has proved a serious 

 disease in very few localities, it receives little attention, and 

 is therefore freely disseminated by commercial intercourse. 

 It is also known in New Zealand and Japan. 



The investigations of Shaw ('13) suggest that Rhizoctonia 

 Solani may be an important disease-inducing organism in 

 some of the more humid regions of India. Reference is made 

 later (pp. 448-450) to the fact that he has obviously misap- 

 plied this name, however, and also that other confusion has 

 resulted. In spite of this, it seems certain that he has ob- 

 served all stages of the fungus. 



TYPES OF DISEASES INDUCED, SYMPTOMS 



It is not my purpose to attempt a complete description of 

 the more important diseases caused by this species, yet suf- 

 ficient will be included to indicate the main types of diseases 

 thus far investigated, their general distribution, and their 

 striking pathological relations. By types of disease, I have 

 reference to general effects or symptoms. The effect of the 

 fungus upon the stems may occasion a different appearance 

 from its action upon the root, and thus there arise the differ- 

 ent types referred to. "With respect to penetration and action up- 

 on the cell the behavior of the fungus may be the same in 

 all cases. Moreover, as a result of the primary injury, second- 

 ary effects may occur, and sometimes such secondary phe- 



