434 Agricultural Experiment Station, Ithaca, N. Y. 



made, and germination commenced before the end of one day^ 

 Tlie conidia became swollen and from one to three germ-tubes 

 were put out. During the succeeding growth, branching occurs 

 freely. The diameter of the threads varies considerably, some be- 

 ing swollen and tapering (Figs. 63 and 64). They contain many 

 vacuoles and granules. At the end of a week, some of the threads 

 become inflated as shown in Figs. 65 and QQ. The growth by this 

 time appears above the agar. The growth is very much branched 

 and closely packed, producing a very dense stellate or coarsely radi- 

 ate growth. In two days more the colonies become tinged with 

 green, by the production of conidia. The growth is so dense that 

 it has been impossible to observe the conidia remaining attached to 

 their sterigmata. Small pieces of the agar covered with conidia 

 bearing mycelium, when placed in water under the microscope,, 

 show a fructification closely resembling that of Penicillium. The 

 branched mycelium bears heads which are branched like Penicillium 

 and which bear long chains of conidia, cylindrical in form and 

 rounded at the ends. A refringent body is usually seen near each 

 end. They measui-e about 3 microns in diameter, and from 6 to 7 

 microns in length. This mass of conidia forms a dense and comj)act 

 covering for the mycelium. 



On potato, the growth spreads over the surface of the potato 

 from the points of inoculation, showing at the end of six days 

 many elevated white points. A marked green color is visible in 

 many places where the mycelium touches the glass ; and where a 

 felt is spread over the surface of the liquid, the entire growth 

 becomes gradually colored a deep bottle-green by the production of 

 conidia. Sometimes a narrow white border is left uncolored. 



The growth is more compact- and the color is darker than in the 

 case of variety americana. The potato and liquid are tinged with 

 green as well as the mycelium where it reaches the walls of the 

 tube. The same columnar structure is seen in the crust of conidia 

 as in the case of the var. americanoj. 



Two cultures were started on the same day in Ehrlmeyer-flasks, 

 filled with sterilized potato to the depth of three-fourths of an inch. 

 One flask was inoculated with conidia of Isaria anisoplioe and the 

 othej with the variety americana. The variety americana grew in 

 a white, elevated, comparatively loose felt all over the surface of 

 the potato. Isaria anisoplim spread comparatively little, growing 

 less vigorously, and in patches not covering more than one-fourth 



