666 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



moss ' Salet ' is here described. It is said to be vigorous, a free flowerer, 

 hardier than most Wichuraianas, and highly ornamentah The 

 branches are covered with small spines as in its moss parent, which for 

 a pole rose which is liable to be planted where it will throw its current 

 year's growth over paths or grass plots is perhaps scarcely a recom- 

 mendation. — M. L. H. 



Roses, Black Spot of. By F. A. Wolf {Bot. Gaz. vol. liv, 

 pp. 218-234; Sept. 1912; 1 plate).— The author describes the black 

 spot leaf disease of roses due to Aciinonema rosae (Lib.) Fries. 



The fungus threads penetrate the mesophyll of the leaf and are 

 connected by hypha3 which pass through or between the epidermal 

 cells to the branched, radiating, anastomo'zing mycelium, which is 

 formed above the epidermis but below the cuticle of the leaf. Conidia 

 are formed from the latter and in great numbers. The cuticle 

 eventually bursts, and the conidia are set free. They germinate readily 

 and can be grown on bean pods. 



Eose leaves kept out of doors in winter in wire cages had formed 

 shield-shaped structures in April. These were found to be the 

 perithecia of the fungus. The asci and paraphyses are formed from 

 tissue which is sub-epidermal, whilst a shield formed of radiating dark 

 brown strands of mycelium, and which is of separate origin, stretches 

 over the top of it above the epidermis but below the cuticle. The 

 author traced the development of ascospores which eventually pile 

 up in a whitish heap in the open perithecium. With these ascospores 

 the author was able to infect rose leaves producing the usual 

 Actinonema rosae. The fungus is described as Diplocarpon rosae, n. g. 

 and n. sp. 



At Pavia only four varieties of the 600 roses grown were 

 apparently free from the fungus. It can, however, be controlled by 

 any of the standard copper compounds. 



Moreover, as it winters in dead leaves, infection can be prevented 

 by collecting and burning all rose leaves in autumn or spring. 



G. F. S. E. 



Roses, Forcing". By A. Buyssens {Rev. Hort. Beige, p. 277; 

 Sept. 1, 1911; plate). — Great quantities of roses are forced in the 

 neighbourhood of Brussels for the Paris, London, Berlin, and other 

 markets. The object of the growers is to produce large, erect roses 

 on long stems which shall be ready to cut through the winter and until 

 the first open-air roses are available. The varieties forced are 

 ' Caroline Testout,' ' Ulrich Brunner, ' * Captain Christy,' 'Mrs. John 

 Lang, ' ' Frau Karl Druschki, ' * Mme. Gabrielle Luizet, ' and ' Kaiserin 

 Augusta Victoria,' and this article gives an exact description of the 

 cultural methods employed. — M. L. H. 



Sap, Ascent of. By A. Ursprung (Beih. Bot. Cent. Bd. 28, 

 pp. 311-322). — The author describes a number of experiments made by 

 himself and others which go to show that living cells of the stem are 



