lyo Transactions British Mycological Society. 



The accompan5dng photograph (fig. i) shows the typical 

 appearance of an old red flux. The tree in question [Ulmus 

 campestris) is on the edge of a field and on the side next the field 

 the base of the trunk has been totally denuded of its bark by 

 horses. From the wood, which has become hard and stony to 

 the touch (owing to the deposition of calcium carbonate), a 

 large flux is exuding. 



These fluxes were found in all sorts of exposures, but appeared 

 to be slightly more prevalent in damp and shady situations. 



We shall consider later the question of the possible causative 

 organisms. 



(b) Organisms present. 



The organism most characteristic of the red flux is a species 

 of Fusarium ; this gives it its red colour. The red masses flowing 

 from the trees are practically "pure cultures" of the Fusarium, 

 and consist of mycelium and spores. 



Very frequently an Oospora [Oidium) of the "Oidium lactis" 

 type, but peculiar in certain respects, is found accompanying 

 the Fusarium. 



The presence of large numbers of bacteria which form 

 fluorescent colonies is noticeable. 

 A. Fusarium. 



This fungus is easily isolated from the red flux by plating 

 it out on such a medium as Dox's agar. 



Cultural characters. On Dox's agar, beer- wort agar, bran agar, 

 oatmeal agar, meat-extract agar, sterile horse-chestnut twigs, 

 sterile potato slants, sterile Lathyrus stems, chunks of elm wood 

 are produced abundant moistslimy " pionnotes " or macroconidial 

 masses, with a sparse, very fine, transparent, cream-coloured or 

 seashell pink (R)* mycelium. Pionnotes varying in colour 

 through carnelian red, rufous, apricot orange and their hues (12, 

 Plate XIV). Marked tendency to mycelial growth in depth of 

 medium. Substratum not discoloured. On steamed rice a very 

 poor growth of pale flesh coloured or flesh coloured (R) mycelium 

 and practically no pionnotes. 



Morphological characters. No microconidia found. Macro- 

 conidia on aerial mycelium or pionnotes, typically triseptate; 

 one end almost straight and tapering, and the other bent at 

 an angle of about 30 degrees to the main axis of the spore. 

 Spores borne on short pedicels and very constant in size and 

 shape, the average dimensions being 23-4 x 3-2 /x. Hyphae 

 average 2-5 ju in diameter, tending to interlace by means of 

 cross connections; terminal and intercalary chlamydospores not 

 uncommon. 



* (R) denotes that the colours have been matched as closely as possible in 

 Ridgway's "Colour Standards." 



