366 Scientific Proceedings, Royal Dublin Society. 



The bell-jars were removed, and subsequently the water-soaked areas 

 became brown and more or less dried up. Ultimately almost every cotyledon 

 of the artificially infected seedlings became attacked and eventually died. 

 Microscopic examination of the diseased cotyledons and stems showed the 

 presence of the fungus (Colletotriehum) in abundance. From these diseased 

 seedlings the fungus was re-isolated in pure culture without any difficulty, 

 and was proved, by comparative cultures, to be identical with that used for 

 inoculation purposes. 



The control seedlings remained perfectly healthy; and the experiment 

 clearly proves that the fungus is pathogenic to flax. 



V. — Previous Studies of Colletotuichum Diseases oe Flax. 



It was not until our pure-culture and infection work had been completed 

 that we became aware that a Colletotriehum disease of flax had already 

 been noted as occurring in the United States of America. It appears that 

 H. L. Bolley, in 1903, 1 first stated that a species of Colletotriehum was very 

 destructive to young flax plants. 



In 1910 this author published a brief description of a disease which he 

 called " Flax Canker," and which he regarded as being caused by a species of 

 Colletotriehum, to which he gave the name ft lini Bolley. 2 The description 

 is altogether too fragmentary to enable us to state whether Bolley's "Flax 

 Canker " is identical with our Colletotriehum disease. In the case of 

 " Canker " the characters of the disease emphasized are the attacks on the 

 stems (usually at ground-level), and the breaking off of the stems at this 

 point as if eaten by insects. Bolley states that : " The general life history 

 simulates that of the wilt fungi, but it is more distinctly cm internal 

 seed disease, 3 and the formaldehyde treatment is not so effective as against 

 wilt . . ." 



A somewhat more extended and illustrated account of " Flax Canker " 

 was published by Bolley 1 two years later ; but the description is of a popular 

 character, and nothing is said of the parasite which causes the disease. 

 Emphasis is, however, again laid on the detection of the disease through the 

 shrunken or concave seeds, and it is maintained that the chief source of 

 transmission of the disease to new areas is to be found in internally infected 

 seeds. 



1 Bull., No. 55. N. Dakota Agrio. Coll. Fargo, 1903. 



2 Bolley, H. L. Seed Disinfection and Crop Production. Bull., No. 87 N. Dakota 

 Agric. Coll. Expt. Station, 1910, p. 144. 



3 Present authors' italics. 



4 Bolley, H. L. Flax Canker. N. Dakota Agric. Expt. Station. Press Bull., No. 52, 

 1912, . 



