368 Scientific Proceedings, Royal Dublin Society. 



With regard to the question of a possible connexion between Colletotri- 

 chum and Gloeosporium on flax we may say that we have also found a species 

 of Gloeosporium on more or less fully grown flax plants, particularly when 

 such plants are suffering from what has been termed "browning" in this 

 country. Whether the Gloeosporium is the cause of this "browning" or 

 not we are not yet in a position to say. We have, however, isolated the 

 fungus, and grown it in pure cultures side by side with our Colletotrichum, 

 and we are quite convinced that the two fungi are totally distinct. The 

 general mode of growth and appearance of the cultures are different. More- 

 over, in our cultures setae were always produced by the Colletotrichum, and 

 never by the Gloeosporium. 



In Holland Gloeosporium Lini has been described 1 as having a Colleto- 

 trichum stage, and as being the cause of a flax disease ; but this fungus 

 appears to be different from ours, and the disease caused by it is evidently 

 not the same. 



VI. — Description of the causative Parasite. 



Descriptions of a considerable number of species of Colletotrichnm have 

 been published from time to time, but we have not been able to identify the 

 species which causes this disease of flax seedlings with any of those hitherto 

 described. 



It may be identical with the species already described (but not named) 

 by Schoevers, and it is just possible that it may be Bolley's C. lini. Since, 

 however, no description of this latter species has been published, the name 

 cannot be regarded as valid. 



In the circumstances we have decided to treat our fungus as a new 

 species, and to describe it as follows : — 



Colletotrichum linicolum nov. spec. 



Acervulis sparsis subepidermicis erumpentibus carneis ; conidiis hyalinis 

 continuis oblongis vel cylindricis vel sub-fusiformibus apicibus obtusis 1-gutta- 

 latis 17yu x 4,u ; basidiis fasciculatis brevissimis simplicibus hyalinis ex 

 parvulis subepidermicis pulvillis ortis ; setulis simplicibus erectis 3-septatis 

 atro-fuligineis acumiuatis apicibus hyalinis 150^ x 4/u ; appresoriis atrofuli- 

 gineis. 



Hah. in foliis stirpibus seminisque vivis Lini usitatissimi in Hibernia. 



No perithecia, pycnidia, resting spores or reproductive bodies other than 



1 Jaarverslag, 1915. Phytopathologisch Laboratorium " Willie Coramelin Scholten." 

 Amsterdam, 1916. 



