376 



Wisconsin State Horticultural Society. 



budding spores. I made many examinations of the pulp to de- 

 tect starch cells, if present, but found none. The fermentation 

 had completely destroyed them, although the starch seemed un- 

 altered. The odor was very bad. The Ohio specimen in No. 1 

 rotted much quicker under the influence of Peronospora infesians 

 than it did under Torula fungus favored by the action of sugar 

 in No. -i solution. The Santa Fe specimen in No. 2 resisted the 

 Peronospora infesians fungus better than it did the Torula fungus 

 in No. 4; but, by the use of either fungus, the tendency of any 

 variety of potato to resist fungus-action may, by this mode, be 

 easily decided. Since the preceding experiments were made, 

 other northern and eastern varieties have been tested by fungoid 

 solutions in contrast with some of the New Mexico varieties, giv- 



FiG. 4. Section Showing Mycelium in Cellular Structure or the Skin. 



ing like results, clearly demonstrating the superiority of the 

 Santa Fe potatoes over all others so examined, in respect to their 

 power to withstand fungoid and infusorial action. 



In examining the skin of an affected potato, I have found on 

 its inner surface generally large quantities of mycelium. (See 

 Fig. 4.) The central portion, C, represents the skin from which 

 the mycelium grows. This form of mycelium I have frequently 

 found in the soil where affected potatoes had grown and decayed. 



