216 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol.. 6 



90 



60 



70 



JO 



/0 - 



p t 



■ 

 2 



h 



Fig. 4. 



to H ion 



Fusarium sp. Graphic representation of the relation of germinal ion 

 concentration. 



Table IV shows that spores of Fusarium sp. are capabl 



de ranee of 



incubation for 6 hours 

 the solution made to te 



After 



C 



H 



no germination is evident in 

 and the same is true with the 



culture testing P H 3.1, in very noticeable contrast with the 



yielded 



oth 



small percentages of germination are obtained 



P 



and germination graduall 



l 



decrease 



hydrogen ion concentration until a very pronounced 



reached 



H 



7 



only to rise suddenly at P 



H 



maximum, the curve dec! 

 + . Upon further incubat 



germination progresses rapidly in the extreme acid cultures, 



that testing P H 2.8 exhibit 



iximum germination on the 



acid side. From this maximum, germination decreases to t 

 culture possessing the exponent 6.2, rises slightly at P H 7 



maximum 



dec 



e in hydrogei 

 being beyond 



concentration, the limiting concen- 



H 



+ 



Examination after incubation f< 

 that no germination is evident at P 



27° C. shows 



H 



noticed 



ubated 



C 



Slight germination occurs at P H 3 



exhibit] 



fall 



H 



5.0. Follow- 



H 



P 



d the typical maximum 



6.2, there occurs a slight rise at 



After this crest is 



