HELMINTHOSPORIUM 481 



a minute Peziza, black ; spores fusiform, ends very acute, 

 5-7-septate, tinged olive, 25-30x6-7 /x. 



Massee,youm. Bd. Agric, Sept. 1902. 



Lime-tree bark disease. The younger branches and shoots 

 of species of Tilia are often completely destroyed by Exo- 

 sporium tiliae (Link.). Numerous black pustules burst through 

 the outer bark, which peels off in flakes, exposing the inner 

 fibrous bast in which the black fruiting bodies of the fungus 

 are embedded. The bast soon becomes broken up into 

 shreds, and I have observed sparrows and other birds stripping 

 it off for nest-building. The white decorticated branches 

 remaining on the trees suggest the presence of the parasite. 



The black spore-beds are subglobose and 1-2 mm. across, 

 and are covered with large, obovate, brownish, 1 -many-septate 

 conidia, 40-70 x 14-18 /x. 



The removal of infected branches during the early stage of 

 the disease would check the extension of the parasite. 



Exosporiiim tiliae (Link.), stroma convex, black, minute. 



HELMINTHOSPORIUM (Link.) 



Conidiophores almost simple, sparsely septate, often nodu- 

 lose, scattered, or usually tufted, coloured ; conidia apical, 

 elongated, 3-many-septate. coloured, epispore smooth. 



Maize blight (Helminthosporium turicum, Pass. = H. incon- 

 spicuum, Cooke and Ellis) often injures maize or Indian 

 corn (Zea mays), and has been recorded from southern 

 Europe, Queensland, and the United States. Small, pale 

 patches appear on the leaves, and continue to increase in size 

 and run into each other, forming large patches, until finally 

 the greater portion of the leaf is covered, the midrib alone 

 remaining rigid. The spots finally change to a light brown, 

 often surrounded by a darker border, and are at this stage 

 more or less covered with a very delicate, dusky mould. In 

 some cases the blotches become much elongated and do not 

 run into each other. The mycelium spreads in the tissue, 

 which finally becomes dry and brittle. The appearance of 

 the fungus fruit depends on weather conditions. If uninter- 

 ruptedly warm and moist, the leaves often become brittle and 

 fall to the ground in fragments before the conidia are formed ; 

 these, however, are produced at a later stage on the fallen 



2H 



