F. J. P. SHAW, 



12c 



of certain liyplise which become .segiueiited into barrel-shaped cells. 

 Hyphse such as these occur in our cultures but are nearly always 

 an early stage in the fornaation of a sclerotium (PI. VII, Figs. 1, 2, 

 3) ; in some cases similar hyj^hae are plentiful in older cultures. 



According to Balls(2) a medium consisting of filter papers in 

 2% solution of asparagin or cane-sugar is most suitable for the form- 

 ation of ' 'resting cells. ' ' Cultures of the Rhizoctonia of ground nut 

 on filter paper moistened with a solution of lactic acid and nutrient 

 salts (see Appendix) gave rise to hyphse with sclerotia consisting 

 of large loosely connected cells (PI. VIII, Figs. 2, 3). In cultures of 

 the Rhizoctonia of cotton on filter paper moistened with 2"^ cane- 

 sugar or asparagin similar structures were formed. 



Inoculations in the laboratory gave different results according 

 to the variety of cotton infected. While Rhizoctonia does not at- 

 tack desi cotton in the field, it caused a mortality of 20 — SO" ^, in the 

 experiment detailed below. In the case of another variety of cot- 

 ton known as "khaki" ' the mortality reached as high as 90 per cent. 



Exferimrnt II. — ••Desi" seed. 



