262 C. D. Sherbakoff 



America. Cause of most of Fusarial rot on potatoes in storage, often 

 occurring in association with other Fusaria. 



The organism was repeatedly isolated by the writer from diseased 

 tubers, and every strain isolated proved capable of producing more or 

 less dark-colored dry rot on tubers. It may be mentioned here that a 

 white rot of tubers can be produced by certain species of Fusarium of the 

 Elegans section, such as F. lutulatum. A rot distinctly striate in ap- 

 pearance was often produced by inoculation with F. striatum; a brownish 

 rot of tubers is caused by F. trichothecioides; and a more or less pinkish 

 rot with large cavities, more or less covered with red masses of macro- 

 conidia, is produced by F. subulatum and F. subulatum var. brevius. 



Of all these, F. coeruleum is the commonest and most vigorous wound 

 parasite of potato tubers; the next, perhaps, is F. subulatum and its 

 variety. 



Measurements of conidia of a few strains of the species on different 

 media are as follows: 



On slightly acidified hard potato agar, culture twenty-two days old; 

 conidia from pseudopionnotes, strain 66: 

 Conidia: 0-septate, 5 per cent, 16 x 4.7 (6-28 x 4.3-5.5)// 

 1-septate, 9 per cent, 21 x 4.7 (17-27 x 4.4-5.3)// 

 2-septate, 10 per cent, 25 x 5.3 (18-32 x 4.6-5.9) // 

 3-septate, 75 per cent, 30 x 5.4 (20-40 x 4.7-6.1)// 

 4-septate, 1 per cent, 36 x 5.5 (33-40 x 5.2-6. 1)// 



On red raspberry cane plug, culture seventy-nine days old; conidia from 

 a sporodochium, strain 66; 3-septate, up to 100 per cent, 33x5.4 (22- 

 40 x 4.8-6) // ; average septation being 

 Conidia: 0-septate, 3 per cent 



1-septate, 11 per cent 



2-septate, 8 per cent 



3-septate, 78 per cent 



4-septate, rare 



On corn meal agar, culture one hundred and seventy-five days old; 

 strain 53 ; very few conidia observed ; chlamydospores numerous : 

 Chlamydospores: 0-septate, 8 x 7.5 (5.2-10.5 x 5.2-9) // 

 1-septate, 11.7 x 7.7 (9.2-14 x 7-8.5)// 

 Also in chains in mycelium, 9 (7.8-11)// in diameter 



