FUNGOID PESTS OF CULTIVATED PLANTS. 29 



Further investigation is advisable, but it certainly is not the Italian 

 species. 



Gard. Chron. 1902, April 12, p. 265. 



VIOLET BLACK MOULDS. 

 Cercospora Viola (Sacc.), PL II. fig. 26. 



This destructive genus of black moulds has no fewer than six repre- 

 sentatives, which attack members of the Violet family. They form spots 

 on the leaves, and develop tufts of short erect threads upon the spots. 

 These threads are each surmounted by a long slender spore, which in 

 most cases is septate, or divided by transverse partitions, and is gradually 

 attenuated upwards almost to a point. 



The British species (Cercospora Viola] has five or six rounded white 

 spots on each leaf, upon which the mould is developed. 



The threads are very short, but the spores are very long (150-200 

 x SJ /i), attenuated upwards, divided by numerous transverse partitions, 

 threads and spores having a smoky tinge. 



It occurs also in Italy, Austria, and the United States. 



It is recommended to spray with dilute Bordeaux mixture. 



Sacc. Syll. iv. 2087 ; Sacc. F. Ital. t. 651 ; Mass. PI. Dis. 819. 



Another species (C. Viola -tricolor is), with longer olive threads, occurs 

 in Italy. 



A species (C. Viola- sylvatica), with shorter spores (45-70 p), is found 

 on Viola sylvatica in the Netherlands. 



A British species (Cercospora li) has been found in Scotland on Viola 

 palustris, with short spores (20-60 p). 



In the United States Cercospora murina,wikh spores (25-35 x 4-5 p), 

 has occurred on Viola cucullata, and Cercospora granuliformis, with 

 variable spores on the same host. 



In Saxony C. lilacina has curved or sickle-shaped conidia (50-75 /* 

 long). 



DISEASES OF CARYOPHYLLACEJE. 



A synopsis of the diseases of the Carnation family has already been 

 published, which did not attempt to include the parasites of uncultivated 

 plants, and yet extended to a considerable length. It will be necessary 

 here to give more explicit details of the several diseases, so that they may 

 be recognised by the ordinary observer. 



Journ. B.H.S. xxvi. 1902, p. 649, PL I. II. 



DIAXTHUS LEAF-SPOT. 

 Phyllosticta Dianthi (West.), PL II. fig. 27. 



This leaf-spot occurs on the foliage of Dianthus barbatus in gardens. 

 It is not a destructive fungus, except to the foliage, which it discolours 

 and distorts to a considerable extent. 



The spots are whitish, and sometimes two or three are run together 

 into one irregular blotch. The receptacles are quite minute, but visible 



