George Raymond Gage 17 



blossoms without touching any of the floral parts. Inoculated blossoms 

 were tagged by means of colored strings. Flowers in a spikelet, not ma- 

 ture at the time of dusting, were removed with a pair of scissors. 



Three days after dusting, flowers of each variety were examined mi- 

 croscopically. As has previously been stated, the majority of the spores 

 had germinated. Those on the stigma seemed to have germinated first 

 (Plate I, 1) — probably due to the sugary excretion as Zacle has sug- 

 gested ; but, in addition, the spores lodged on the ovary walls were also 

 fully germinated at the end of five days. This took place in both the 

 glumed and the glumeless varieties. In no case, however, was sporidial 

 production observed. The average temperature recorded by the United 

 States Weather Bureau Station at Ithaca during this period was 

 slightly under 30° C. 



At the end of twelve days mycelium could be detected in the glumes 

 and in the pericarp epidermis in both varieties. For detection of the 

 mycelium the writer used at first an aqueous solution of eosin, but later, 

 on becoming acquainted with a stain known as "cotton blue," 2 he found 

 it an easy matter to demonstrate the mycelium in both the glume paren- 

 chyma and the pericarp epidermis. This stain was used in all subse- 

 quent mycelial studies. 



When mature, the inoculated oats were harvested and stored in paper 

 bags under ordinary room temperature and moisture conditions. After 

 the uninoculated oats were threshed, part of the glumed variety was 

 dusted with spores without first removing the glumes, and part was 

 dusted with spores after the glumes had been removed. A similar lot of 

 the glumeless oats was dusted also. These supplies of inoculated seed 

 were to be used for testing the relative ability of dormant spores, as com- 

 pared with mycelium, to carry the pathogene over the winter. They 

 were kept under exactly the same conditions as were the blossom-inocu- . 

 lated oats. 



In the following spring, prior to sowing, the blossom-inoculated 

 glumed oats were divided into two lots, one of which was deglumed to 

 remove all pathogene structures which might be on or in the glumes. 



In the spring of 1925 the writer had on hand, then, the following va- 

 riously treated lots of seed oats, with definitely known history in so far 

 as inoculation was concerned : 



1. Swedish Select (glumed) uninoculated. 



"J. Swedish Select inoculated at blossoming time, glumes not removed 

 and therefore with mycelium developed in the floral parts (pos- 

 sibly some ungerminated spores present;. 



-Cotton blue (Blue cotton, G-4 b., Soluble blue) was used as follows: Solution A, 

 consisting of 50 grams of phenol, 50 grams of lactic acid. 50 cubic centimeters of 

 glycerin, 100 cubic centimeters of distilled water. Solution B, the same as A, with 1 

 gram of cotton blue. Material from water was placed in A for a few minutes, then 

 transferred to B for a few minutes, and then returned to A for clearing. 



