28 



in the dormant seed, as in the sprouting seedling, did not differ from those already given for 

 wheat. 



COMPARATIVE SURVEY OF EXPERIMENTAL INFECTION CARRIED OUT WITH THE LOOSE 



SMUT OP BARLEY. 



A. EXPERIMENTAL INFECTION IN 1903. 



L BLOSSOM INFECTION. 



Only a little seed was harvested from the blossom Infection of 1902. This small amount failed com- 

 pletely when sown. 



II. CYLINDER INFECTION. 



1. On June 18, 1902, cylinder infection was undertaken in Grabschen on a field of barley just 

 beginning to bloom. In the middle of the heads chosen a few blossoms were open. From the harvested 

 seed 



1,590 stalks were grown, of which 10.5 per cent were smutted. 



A correspondingly large control with seed from the same field from non-infected heads showed 

 0.1 per cent smutted. 



III. INFECTION OF THE YOUNG GERMINATING SEEDLINGS. 



1. The young, just sprouting seedlings of barley from Munster were infected by spraying with 

 smut spores from the same field. The smut spores had been brought to germinatiion by soaking in water 

 and were then finely divided in dilute nutrient solution. 



Of the 200 stalks transplanted in open ground, 1 per cent was smutted. 

 In the control no smutted stalks were produced. 



2. Two-rowed barley treated as under 1 gave no smutted specimens. The same was true of the 

 control. 



IV. INFECTION OF THE SEED. 



1. Five different varieties of barley were mixed with smut spores, which had been taken from a 



field of each separate kind, and were sown directly on the open ground. From each of them 300 stalks 



were grown. The production of smutted stalks was exactly the same as in the controls produced from 

 sterilized seed. 



B. EXPERIMENTAL INFECTIONS IN 1904. 



I. BLOSSOM INFECTION. 



1. Land barley (Landgerste) from Mun,ster was infected in 1903 in the separate blossoms with 

 fresh barley smut spores from the same field. 



a. Before blossoming. 



b. Just when the heads were blossoming. 



At the end of March, 1904, the sterilized grain was sown on sterilized sand from the river Oder in 

 closed germinating cases. On April 22, 1904, the young seedlings were transplanted to open ground. 



a. From the grains infected before blossoming 



104 stalks were developed, of which 17 per cent were smutted. 



b. From the grain infected during blossoming 



350 stalks were developed, of which 60 per cent were smutted. 

 The control from sterilized seed from non -infected heads of the same field gave no smutted speci- 

 mens in 300 stalks. 



2. On June 30, 1903, heads of a two-rowed Hanna barley just blossoming were infected in the 

 single blossoms with fresh smut spores from the same field. The seed was sown in 1904 as given under 1. 



300 stalks were developed, of which 57 per cent were smutted. 

 A control of sterilized seed from non-infected heads of the same field gave no smutted specimens in 

 250 stalks. 



3. Land barley from Grabschen was infected on July 1, 1903, in the separate blossoms, with smut 

 spores from the same field. 



a. Shortly before blossoming. 



b. From heads just blossoming. 

 The sowing in 1904 resulted in, 



a. 85 stalks, of which 30 per cent were smutted. 



b. 162 78 " 



