12 CIRCULAR NO. 131, BUREAU OF PLANT INDUSTRY. 



by Anderson. At the end of 3 or 4 days E. parasitica at room tem- 

 perature showed a short, fluffy, white, aerial growth along the streak. 

 The surface of the mycelium was orange by transmitted light, while 

 by reflected light it was between raw sienna and antique brown at the 

 sides. Withm 6 days the mycelium, especially at the base of the agar 

 slant, took on a peculiar granular metallic appearance, due apparently, 

 m part at least, to the character of the mycelium and in part to the 

 minute water drops scattered over the surface. This portion of the 

 culture was light orange yellow by reflected light and orange by 

 transmitted light. The peculiar surface appearance might perhaps 

 be called "brassy." This metallic appearance has been found to be 

 the most constant and reliable distinguishing character of E. para 

 sitica on potato agar. In 12 to 14 days small pycnidial pustules 

 appeared in the upper portion of the tubes, and the agar just below 

 the mycelium became warbler green, changing later to olive green. 



EndotJiia radicalis. — Pycnospore streak cultures of this species vary 

 widely as to the amount and time of the appearance of color. Occa- 

 sionally tubes showed a small orange area m 5 days. Many tubes 

 showed the same color in 1 week, while others produced no orange 

 color whatever. In no case did cultures of EndotJiia radicalis produce 

 the brassy metallic surface so characteristic of E. parasitica. Pycnidia 

 were few and more scattered than in E. parasitica and spore masses 

 did not begm to appear until the thu'd or fourth week. A slight 

 amount of warbler-green color appeared in the medium occasionally 

 at this age, but never so conspicuously as m E. parasitica. 



Cultures made by transfer of mycelium of EndotMa radicalis to 

 potato agar were found to vary widely as to the rate of growth, color, 

 and general appearance. The variations in such cultures were so 

 great as to make them much less reliable than spore cultures. 



EndotMa radicalis mississippiensis. — ^This produced less fluffy 

 aerial mycelium along the spore streak than Endotliia parasitica. 

 After 5 or 6 days the fungus showed an orange color by transmitted 

 light and was indistinguishable in this respect from E. parasilica. 

 The character of the surface was somewhat different, however, and 

 by reflected light appeared xanthine orange. "V\Tien 2 weeks old this 

 form differed stifl more markedly from E. parasitica in color, being 

 grenadme red by transmitted light and showing no spore masses. 



Endotliia gyrosa. — This species developed more slowly than any of 

 the others, producing a rather abundant aerial growth, which was 

 felty rather than fluffy. The color was white flecked with capucine 

 buff, and no spore masses were produced. 



On potato agar of high acidity, i. e., from +11 to +15, no spores 

 were produced in any of the specirs, even in very old cultures. In 

 agar of lower acidity, spore production was proportionately greater, 



[Cir. i:;i] 



