298 



NINETEENTH REPORT. 



Table 6. 



Vegetable Media. 



Medium. 

 Potato. 



Parsnip. 



Carrot. 



Red table beet. 

 Sugar beet. 

 Clover stem. 



Sorghum stem. 



Corn meal. 



6 days. 



About one-half of surface 

 covered by a dark gray 

 growth. Very few spores 

 mostly immature. Mycelium 

 toruloid and coarsely gran- 

 ular. 



18 days. 



Growth is black almost 

 completely enveloping the 

 plug. Growth is somewhat 

 brittle, forming a crust about 

 3 mm. thick. Interior of 

 potato is disorganized and 

 permeated with a hyalin 

 mycelium. Spores very few. 



General appearance, texture, amount of growth, and 

 mycelium like that on potato, but spores are much more num- 

 erous. 



About two-thirds of sur- 

 face covered by dark gray 

 growth; spores abundant. 



Black dense growth; spores 

 abundant. 



Like table beet. 



Black scattered growth; 

 spores abundant. 



Black growth ; spores 

 abundant ; more vegetative 



mycelium than on clover 

 stem. 



About two-thirds of sur- 

 face covered by growth; 

 spores abundant. 



Black brittle growth sim- 

 ilar to that above. 



Like carrot. Spore pro- 

 duction best of series. 



Slight greenish tinge; other- 

 wise like red table beet. 



Surface growth mostly of 

 short conidiophores covering 

 entire stem; superficial 

 mycelium slight. Interior 

 pervaded by hyalin threads. 



Ditto, except for more 

 mycelium. 



Growth has ramified 

 throughout the meal, blacken- 

 ing it. Much better than on 

 corn meal agar. 



On culture media the fungus exhibits many variations in the form and 

 structure of the mycelium which are not found when the fungus is grow- 

 ing within the host. In cultures which are well developed (2-3 weeks), 

 the cells of some of the mycelium are closely packed with highly refract- 

 ive globules, — mostly oiP. Other cells contain only a few larger 

 globules, and an occasional cell may be seen completely filled by a 

 single oil globule. Individual cells ma}' swell up and assume a globular 

 form, with a diameter of 8-11 microns. The submerged mycelium differs 

 from that growing on the surface in that it is toruloid or beaded. Some 

 of these cells form internal cross walls and appear almost like the 



•Test for oil made with Sudan III; the oil globules were stained light red by this 

 preparation. 



