•2 



JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



are colourless, elliptical (8-10 x 6-7 v)> and readily fall away. These galls 

 differ essentially from the peach blister in the spores being naked and 

 exposed, not enclosed in asci, and in being produced upon the outer 

 and convex, not on the inner and concave surface. 

 Known also in France and Germany. 



Diseased leaves should be burnt as soon as the fungus shows itself, 

 and before spores are produced. 



Sacc. Syll. Hym. ii. 7797 ; Gaul. Chron. 1879, p. 119, 182; Mass. 

 PI. Dis. 168, 398, fig. 



Similar galls are produced on Bay-Laurel. 



Rhododendron Leaf-spots. 



Several kinds of leaf -spot are known on species of Rhododendron, but 

 have never caused anxiety, as they simply disfigure the leaves. Some of 

 these may be enumerated. 



Phyllosticta Saccardoi, forming orbicular spots with a tawny margin, 

 and small sporules (4 x 1 in France and Portugal. 



Phyllosticta rhododendricola, with large irregular grey spots having 

 a brown margin, and larger sporules (8-10 x3/j), in France. 



Phyllosticta rhododendri, with rusty-brown spots, chiefly marginal, 

 and the sporules oozing out in flesh-coloured tendrils. Found in Belgium 

 and Britain. 



Phyllosticta maxima, with large brown spots with dark margin, and 

 rather large sporules (10-12 x6-8^), confined to North America ; with 



Septoria rhododendri, having orbicular pallid spots girt by a dark 

 purple margin, and thread-like sporules (40 /i long), and a similar 



Septoria solitaria, with sporidia half as long, on Rhododendron occi- 

 dentals in California. 



There are also two species of anthracnose known. 



Glceosporium rhododendri, with large irregular spots, which are 

 zoned, and have a black margin, the sporules 15-20 x 4-5 /j, found in Italy, 

 but not certainly British. And 



Glceosporium succineum, with sporules about the same size, but 

 globose and yellowish. Altogether a doubtful Siberian species. 



Rhododendron Brand. 

 Puccinia rhododendri (Fckl.). 



This brand has been found on the under surface of the leaves of 

 Rhododendron ferrugineum in the Tyrol, but there is no record of it else- 

 where. The teleutospores are ovate, slightly constricted at the middle (26 

 x 18 /u), brown. 



Sacc. Syll vii. 2474. 



A^rust on the leaves of Rhododendron ferrugineum, dauricum, and 

 hirsutum, distinct from the above, has been found in Italy, France, 



