FUNGOID PESTS OF CULTIVATED PLANTS. 43 



Septoria Bosa is probably distinct, and occurs in Belgium, France, 

 Italy, Portugal, and Algeria. The spots are brownish and the sporules 

 larger (70-90x3 1-4 /u). 



KOSE-LEAF BLACK BLOTCH. 

 Actinonema Bosa (Lib.), PL III. fig. 50. 



This very common blotch on Rose leaves is to be seen in almost every 

 garden, and many cultivators treat it as of small account, except for 

 disfiguring the foliage. 



The spots are somewhat rounded, and from half an inch to an inch 

 broad, on the upper surface of the leaves, at first purplish and then 

 black, without any well-defined margin. On the spots becoming black, 

 closely adherent, flexuous, weblike lines radiate from the centre of the 

 spot. Here and there are scattered the small black conceptacles, or peri- 

 thecia, which contain the sporules. The latter are composed of two 

 obovate cells, attached together by their broader ends (18-20 x 5 /u), each 

 containing two small nuclei, or guttules. The perithecia certainly are 

 very obscure and difficult to discover, but sporules are readily found. 

 Some authors deny the presence of perithecia altogether. 



This parasite has been recorded in Great Britain, France, Belgium,. 

 Germany, Sweden, Austria, Italy, Portugal, and the United States. 



If all diseased leaves were to be collected and burnt, scarcely a leaf 

 would be left on some Eose bushes. Spraying has been recommended 

 with diluted copper sulphates. Blue water, or Eau Celeste, is a prepara- 

 tion much in vogue with some cultivators, and is said to be of much 

 service. 



Sacc. Syll. iii. 2257 ; Cooke Hdbk. No. 1372 ; Tubeuf, Dis. 474. 



ROSE RUST. 

 Uredo Bos (Pers.), PL III. fig. 61o. 



The uredines, or rusts of different kinds, are rather partial to the 

 Rose family, and this, which is the uredo stage of a more elaborate 

 fungus, hereafter described, has been known at different times as Uredo 

 pinguis and Uredo miniata. It occurs on the leaves, petioles, and stems 

 of cultivated Roses, bursting through the cuticle as a yellow powder. 



The under surface of the leaves is sprinkled with the small pustules, 

 either scattered or gathered together, which soon discharge the uredo- 

 spores, which are rather variable in form, spherical, ovoid, or angular 

 (17-32 x 12-24 /;), with a minutely roughened surface. 



Early in the year this yellow uredo may be detected upon the leaves, 

 without any indication of the teleutospores which are to follow. 



It is remarkable how this pest seems to follow the cultivation of Roses 

 all over the world, and no efforts seem to make much progress towards- 

 either its extirpation or mitigation. 



It may be said to be universal throughout Europe, and to have- 

 extended to Asiatic Siberia, probably to India and to South Africa. 



It is recommended that plants which have been attacked the previous 

 season should be drenched with a solution of copper sulphate in water, in 



