88 Journal of Agricultural Research voi. xni, No. 2 



CONIDIA FROM ASRIAL MYCELIUM ON" STRING-BEAN AGAR, CULTURE 6l DAYS OLD 



Microconidia: 



o-septate 12 per cent, 8 by 2.5 (6 to 12 by 1.5 to 3) fx. 

 Macroconidia: 



i-septate 15 per cent, 13 by 3 (10 to 18 by 2.8 to ;i.6) n. 



2-septate 8 per cent, 18 by 2,-S (14 to 21 by 3 to 4) m- 



3-septate 61 per cent, 24 by 4.4 (19 to 37 by 3.5 to 5) 11. 



4-septate 3 per cent, 29 by 4.5 (19 to 42 by 3.5 to 5.2) /i. 



5-septate I per cent, 30 by 4.6 (26 to 43 by 4 to 5.2) n. 



SUMMARY AND AVERAGE OP THE FOREGOING MEASUREMENTS 



Microconidia: 



o-septate up to 21 per cent, 7 by 2.4 (4 to 12 by 1.5 to 3.5) m- 

 Macroconidia: 



i-septate up to 15 per cent, 14.7 by 3.1 (9 to 19 by 2 to 3.7) ii. 



2-septate up to 19 per cent, 17 by ^.t, (12 to 21 by 2.5 to 4) m- 



3-septate up to 72 per cent, 25.5 by 4.1 (18 to 40 by 3 to 5) m- 



4-septate up to 7 per cent, 29.7 by 4.4 (19 to 42 by 3.5 to 5.2) ix. 



5-septate up to I per cent, 32 by 4.4 (26 to 43 by 3.8 to 5.2) m- 



Section Discolor 

 (2, 5, 6, g, 18, 19, p. 206; 22, drawing joj). 

 Fusariiim trichothecioides WoUenw. 



The organism isolated agreed in every particular with the original 

 description given by Wollenweber (5) . On comparing it with a strain 

 of F. trichothecioides used by the writer in previous experiments it was 

 found to be identical. The organism isolated from the soil was inocu- 

 lated into potato tubers and a tj^pical powdery-dryrot produced. 



Habitat: First reported in 191 2 by Jamieson and Wollenweber (5) on 

 potato tubers from Western States and demonstrated to be the cause of 

 a dry rot of western potatoes and capable of attacking growing plants. 

 In 191 3 a species of Fusarium, called " Fusarium tuherivoriitn Wilcox 

 and lyink," was reported as causing a dry rot of potatoes in Nebraska 

 by Wilcox, Link, and Pool {18). This fungus was demonstrated by 

 Wollenweber (19, p. 206) and by Carpenter (2) to be identical with F. 

 trichothecioides Wollenw., which opinion was later concurred in by one 

 of the authors of F. iuberivorum (6), who demonstrated it to be a cause 

 of potato-wilt. Investigations on the part of the writer failed to prove 

 it a wilt-producing organism under ordinary field conditions in Idaho, 

 but demonstrated it to be a prevalent cause of storage-dryrot in that 

 State (9). Isolated twice from Idaho soils from sample 3. 



Fusarium culmorum var. leteius Sherb. (14, p. 242-244, pi. 4, fig. i, 2, 10; pi. 5, fig. 

 g, text fig. iD^, 43): 



No authentic culture of the original strain of this organism was avail- 

 able for comparison, but the conidial dimensions and growth characters 

 were so similar to those of the original description given by Sherbakoff 



