FusARiA OF Potatoes 141 



Differs from F. caudatum Wr. (see WoUenweber 1914:262-263, PL xvi, 

 fig. m) mainly by broader conidia, which in the latter organism average 

 only from 3 to 4.5/i in diameter. 



The organism was twice isolated, in 1912 and in 1913, from superficial 

 dry rot of potato tubers collected at Atlanta, New York. The measure- 

 ments of conidia on different media are as follows: 



On red raspberry cane plug, culture sixty-nine days old: 

 Conidia: 3-septate, 10 per cent, 30x4 (26-35 x 3.5-4.5) /x 

 4-septate, 5 per cent, 34 x 4.4 (32-40 x 4^.8) /i 

 5-septate, 85 per cent, 40 x 4.8 (33-55 x 4-5.4) /x 



On slightly acidified hard potato agar, culture nine days old: 

 Conidia : 3-septate, 1 per cent, about 38 x 4ju (only a few measured) 

 4-septate, 8 per cent, about 40 x 4.2/x (only a few measured) 

 5-septate, 43 per cent, 55 x 4.3 (38-69 x 3.5-5.9)^1 

 6-septate, 27 per cent, 65x4.4 (55-84 x 4. 1-5.3) ^ 

 7-septate, 21 per cent, 69 x 4.4 (60-85 x 4. 1-5.9) /x 

 8-septate, very rare 



On hard lima-bean agar with 2 per cent glucose, culture one hundred 



and eighteen days old: 



Conidia: 4-septate, 1 per cent 



5-septate, 29 per cent, 46 x 4.7 (43-59 x 4.3-5.2) /x 

 6-septate, 32 per cent, 53 x 4.8 (48-60 x 4.3-5) m 

 7-septate, 37 per cent, 57 x 4.8 (50-62 x 4.7-5) m 

 8-septate, 1 per cent, 61 x 5^t (only one measured) 



On hard lima-bean agar, culture nine days old: 

 Conidia: 5-septate, 55 per cent, 52 x 4.5 (45-61 x 4-4.8)^1 

 6-septate, 35 per cent, 65 x 4.7 (55-71 x 4.3-4.8) /x 

 . 7-septate, 10 per cent, 68x4.7 (58-78 x 4.3-4.8) /x 



Average of the above measurements: 

 Conidia: 3-septate, 3 per cent, 34x4/x 

 4-septate, 3.5 per cent, 37 x 4/x 

 5-septate, 53 per cent, 48 x 4.6^t 

 6-septate, 23.5 per cent, 58 x 4.6)U 

 7-septate, 17 per cent, 64.7 x 4.6/x 

 8-septate, rare, 61 x 5/x (only one measured) 



