1907] 



STEVENS— CHRYSANTHEMUM RAY BLIGHT 



249 



\ 



I 



Plate 



Medium 



5- 

 6. 



3- 

 4- 



39 

 40 



Standard 

 beef agar 



Cow pea 

 agar 



Standard 

 beef gelatin 



Dec. 8 



Dec. 9 



Dec. 10 



1 



Dec. II 



1 



Dec. 12 



Dec. 13 



Dec. 14 



Dec. IS 







1 



12-20° 



12-20° 



i 



18-21° 



17-21° 



18-20° 



Grew 



■ ^ 



i-S 



1 



2 



1 



s 



9 



10 



II 



14 



a 



1-5 



2 



5 



10 



12 



13 



15 



ii 



2 



3 ' 



S 



12 



14 



18 



22 



<t 



2 



3 



5 



12 



14 



18 



22 



it 



2 



2 



4 



6 



1 



8 



II 



15 



tt 



2 



2 



4 



6 



1 



10 



12 



15 



Jan. 12 



52 

 32 



35 



• * 



Colonics grown in pure agar in dark or light and those upon pea agar 

 were of the same general appearance, thin, colorless, and structure- 

 less, zone formation being entirely absent. A very few pycnidia were 

 produced. By increasing the richness of the pea agar to 4 per cent-, 

 pycnidia were secured, but without change in other characters. The 

 growth in pea agar was no more rapid than that on pure agar, but was 



developed- 



very 



pepl 



medium for this fungus. Growth comes to an end earlier than in 

 pure agar or other media; there are no pycnidia, no color to the 

 mycelium, and only a very slight indication of zonation. 



Glucose y 1 and 5 per cent., favor growth, the five per cent, being 

 slightly better than the one per cent. No pycnidia developed, but 

 there is marked, though irregular, zonation in both darkness and light, 



:elium develops a striking, intense blackness. 



and the whole 



m\ 



The septation and cell contents are normal 

 with the cell wall. 



the color rests 



growth 



upon microscopic 



were digested almost as soon as the advancing threads of the fungus 

 reached them, and growth continued long in these plates. The 

 effect of starch upon the general appearance of the colony and upon 

 the mycelium was precisely as in the glucose plates. 



In standard beef agar and gelatin^ growth was about as with pep- 

 tone agar, though it continued for a longer time. The mycelium was 



o 



ifig 



beef 



