Parasitic and Saprophytic Fungi in Orchards. 165 



spores in the air. At various times from May 1, 1901, to May 1, 

 1903, he placed petri-dishes with gelatine in the garden, hospital, 

 and laboratory. He made counts of the number of fungi found. 

 Temperature, rain, and wind had a very great influence upon the 

 number of spores present in any locality, but there was little 

 or no difference at the same time in the different locations. The 

 most abundant were Cladosporiuni hcrharum, Penicilliiim qlaucum 

 and Epicoccnm purpurascens; next came Aspergillus glaucus, 

 Catenularia juligena, Alucor racemosus, Rhizopus nigricans, 

 Macrosporium dados poroides, and Monilia sp. 



In the summer months, Botrytis cinerea and Verticillium 

 glaucum were the most abundant in the atmosphere of the garden, 

 and in the winter, Heterohotrys sp. and Fusarium roseum. 



This paper is concerned only with those forms which are 

 found in orchards. The aim of the work was to determine what 

 parasitic or saprophytic fungi were present at dift'erent periods 

 of the year, by exposing petri-dishes containing glucose agar. 



METHOD. 



The orchard which was made the basis for the work was in 

 Field 6, at the Nebraska State Farm. Three stations were 

 chosen at which to make the exposures each time. By securing 

 uniformity of location for each exposure, it was hoped to get 

 more uniformity in results. One station was chosen in a portion 

 of the orchard where the ground cover was clover and alfalfa, 

 another in which absolutely clean cultivation, nothing being 

 permitted to grow on the ground, was practiced, and another 

 in which the cover was millet stubble. 



In every case, the medium used in the trap cultures has been 

 glucose agar, made by adding glucose enough to equal 3% of 

 the weight of the plain agar with the reaction plus 10. Special 

 experiments have involved the use of other media. This was 

 done partly in the hope of determining more of the habits of the 

 various fungi and partly to aid in determining the species. It 

 was not hoped by this means alone to ascertain definitely the 

 species, yet mycological literature is full of descriptions of fungi, 

 in which brief notes upon a single colony on a named substratum 

 are the only bases of identification. In these a spore measure- 

 ment is seldom found. 



