FUNGOID PESTS OF CULTIVATED PLANTS. 38 



which are yellowish-brown and angular from mutual pressure. The 

 outer surface is rough with little tubercles and ridges (12-18 x 10-14 /A). 

 The spores have been induced to germinate artificially, but not to proceed 

 to the formation of secondary spores. 



In the majority of species of the "smuts " the spores and glomerules 

 are very dark brown, or almost black, and hence the name ; but in a few 

 species and this amongst the number the colour is pale. 



Undoubtedly the smuts may be disseminated by means of the spores, 

 but at the same time there is strong evidence in support of a perennial 

 mycelium in perennial plants. 



The present species is known in France, Germany, Austria, Italy, and 

 Algeria, as well as Britain. 



Difficult to combat, but seldom occurs in this country. Better to burn 

 infected plants. 



Sacc. Syll. vii. 1872 ; Plowr. Brit. Ured. p. 296 ; Mass. B. F. p. 202, 

 figs. 59, 59A ; Journ. E.H.S. 1902, p. 650, PI. II., f. 9. 



ANTHER SMUT. 

 Ustilago violacea (Pers.), PL II. fig. 33. 



This smut habitually attacks the flowers of many species of Caryo- 

 phyllacecB, chiefly appropriating the anthers, and converting them into a 

 mass of blackish powdery spores, which are diffused and scattered over 

 the petals. In older books it is known as Ustilago anther arum from its 

 habit of growth. 



The spores are subglobose and lilac under the microscope, covered 

 with a network of ridges (6-9 /u diam.), the meshes being about \ p apart. 

 On germination a fusiform promycelium is formed, which is commonly 

 three-septate, each joint giving origin to a secondary spore, or sporidiole, 

 of an ovate form. 



This species is known also in France, Belgium, Germany, Switzerland, 

 Austria, Bohemia, Transylvania, Italy, and North America. 



Naturally there can be no remedy, as the presence of the parasite is 

 unknown until it makes its appearance in the flowers, and then it is too 

 la.te. All that can be done is to destroy all infected plants, so as to pre- 

 vent the spread of the disease. 



Sacc. Syll. vii. 1781 ; Cooke M. F., figs. 102-104 ; Plowr. Brit. Ured. 

 p. 280 ; Mass. B. F. p. 179 ; Cooke Hdbk. No. 1534 ; Journ. B.H.S. 

 1902, p. 651, PL II., f. 11 ; Tubeuf, Dis. p. 297. 



1 SWEET WILLIAM BRAND. 

 Puccinia Dianthi (DC.), PL II. fig. 35. 



One of the most common and best known pests of Sweet Williams 

 and other allied plants, attacking the living foliage and rendering them 

 most unsightly. There are usually large pale spots upon the leaves, 

 which are somewhat rounded, or one or two other spots are joined to 

 make them irregular, or to occupy nearly the whole of the surface of the 

 leaf. 



The pustules are rounded and cushion-like, either disposed in circles 

 on the spots, or running together and forming an irregular crust, which 



D 



