PESTS OF THE FLOWER GARDEN. 



45 



membrane, without orifice, and the gelatinous contents. When quite 

 mature each receptacle encloses a single globose transparent sac, or 

 ascus, which holds numerous elliptical uncoloured spores (20-27 x 12-1 5 n). 



When the patches of mould upon the leaves have produced their 

 conidia, the leaves generally curl up and fall away without producing the 

 receptacles. On the stems and ovaries the perithecia are to be found, 

 and within them the ascospores, or perfect spores, are produced. 



The treatment suggested resembles that which has been successful in 

 the allied Hop disease — flowers of sulphur mixed with about one- third 

 of its volume of slaked lime dusted upon the foliage. Spraying with 

 potassium sulphide solution has been recommended as equally efficacious. 

 In this, as in all similar cases, it cannot be too strongly urged that all 

 the diseased parts possible should be cut off and burnt to prevent the 

 dissemination of the conidia and spores. Vigorous treatment would 

 minimise disease. 



Sacc. Syll i. 6 ; Cooke M. F. 169, 238, figs. 217, 218 ; Mass. Bis. PL 

 444 ; Tubeuf. Dis. 172, fig. 



Rose Tumouk. 

 Botryo splicer ia diplodia (Moug.), PL III., fig. 53. 



The living stems of Roses are often disfigured by the occurrence of 

 blackish elliptical swellings or cancerous -looking spots marked with 

 darker concentric lines. In former times they were called by the name 

 of Dothidea Bosce (Fr.), but names are apt to change. 



The stroma, or tumour, is developed beneath the bark, and is of a 

 tawny colour, in which the globose perithecia are immersed, becoming 

 more or less erumpent, splitting the cuticle into flexuous fissures. The 

 perithecia are rather crowded in this stroma, or tubercle, and are some- 

 what slow in arriving at maturity, when they contain numerous club- 

 shaped hyaline asci, or specialised cells, which enclose eight sporidia in 

 each, arranged in a double row. These sporidia are almond-shaped and 

 colourless, or tinged with yellow (17-20x8-9 /*), escaping and becoming 

 free when mature. 



We have no knowledge of any experiments in combating this disease, 

 but presume that it is deep-seated, and has permeated the tissues before 

 it makes any external appearance. 



The distribution of this species is given as Britain, France, Belgium, 

 Germany, and Italy. 



Sacc. Syll. i. 1774 ; Cooke Hdbk. No. 2425 ; Berk. Eng. FL v. 255. 



(To be continued.) 



