SPORIDESMIUM 499 



Heterosporium gracile (Sacc.) is the cause of injury to the 

 leaves of various cultivated plants Iris, Hemerocallis, Freesia, 

 Antholyza, etc., and is recorded from Europe, South Africa, 

 New Zealand, and the United States. Large brown spots 

 with a darker margin are usually present in considerable 

 numbers on the leaves, which soon wilt and die in con- 

 sequence. 



Conidiophores olive, septate, nodulose, 70-90X10-14 /*. 

 Conidia elliptic-oblong, i-3-septate, ends blunt, minutely 

 warted or granular, pale olive, 70 X 14-20 /*. 



I found that spraying with ammoniacal copper solution 

 checked the progress of the disease in the case of Freesia 

 recurva. Probably sulphide of potassium would answer 

 equally well. 



Spinach leaf spot (^Heterosporium variabile, Cooke) often 

 forms roundish or irregular spots of a pale yellowish colour 

 on the living leaves of spinach, which in consequence wilt 

 and die. When the fungus is present in quantity the produce 

 is often much reduced. When the diseased spots become 

 clearly defined, the surface is studded with minute, dark- 

 coloured tufts of fungus fruit. 



Conidiophores flexuous, slender, more or less nodulose at 

 the septa. Conidia cylindric-oblong, the larger ones 2-4- 

 septate, epispore minutely warted, 20-25x7-10 JJL. Conidio- 

 phores and conidia pale olive colour by transmitted light. 



*** Spores muriformly septate. 



SPORIDESMIUM (LINK.) 



Mycelium generally scanty, conidia ovate or obclavate, 

 usually large, septate, becoming muriform, coloured. 



Potato leaf blotch. This is a disease well known on the 

 Continent, also in Ireland, but has only quite recently been 

 observed in Britain. The foliage is the part attacked, the 

 parasite, Sporidesmium solani varians (Vanha), forming 

 small, scattered, brown ""spots on the leaves. These spots 

 gradually increase in size and fuse together, forming well- 

 defined, blackish-brown patches. Leaves that are attacked 

 soon turn blackish and die. When this happens somewhat 



