IIoMMA: A Statistical Study on the Bioloc.uai. I'OKMs oi' KuvsirnE ckaminis DC. l6l 



R E S U M E 



No previous record of the comparative study on the morphology of the 

 biological forms of Erysiphc graiiiiiiis could be found. In tliis summer, the writer 

 intended to determine the differences in tlie dimensions of the conidia of these 

 biological forms. The material used in this study was collected at Sapporo and 

 its vicinity. The form on the common wheat was lirysiphc graniiiiis f. sp. 

 Tritici ; on the naked barley it was f sp. Hordi ; on Poa annua it was f sp. 

 Poac ; and on E/yinus mollis it was f s|3. Elymi which is newly proposed by 

 the writer. Five hundred conidia of each of the first three forms and one 

 hundred of the last were measured. The mean values for the length and width 

 of each forms were as follows : 



f, sp. Tritici 37-35 ±0037 14.50io.035 



f. sp. Hordi 35.45 ±0.078 14.64 ±0.040 



f. sp. Poae 3i.co±o.o54 16.31 ±0.043 



f. sp. Elymi 26.67 ±0.144 13 84 ±0.068 



From tliese results, we can easily recognize the differences in the spore- 

 size of these biological forms of Erysiphe graviinis. 



Oct, 1928 



