18 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Britain, and their geographical distribution includes France, Switzerland, 

 Germany, Finland, and Siberia. 



Never likely to cause sufficient trouble to call in the aid of fungicides, 

 better to pick off the diseased leaves if the cups appear. 



Sacc. Syll. vii. 2710 ; Pers. Ic. Pict. iv. t. 23, f. 4 ; Cooke Hdbk. 

 No. 1616a ; Plowr. Br. Ur. 263. 



P^ony Leaf-spot. 



PhyUosticta Pceonice (S. & Sp.), PI. I. fig. 11. 



P&ony leaves are subject to several kinds of leaf- spot in different 

 countries, but only the above has at present been recorded for Britain. 

 This scarcely deserves to be called a " leaf- spot," since the spots are 

 obsolete, and the rather large perithecia are scattered, like little black dots, 

 over the leaves. 



The conidia are elliptical, with two nuclei (10 x 5 ^), and have a 

 slight tinge of olive. 



The greatest harm that the majority of these leaf -spots do to the 

 plants is to disfigure the foliage. In general they may be kept in check 

 by spraying and picking off the infested leaves. 



Sacc. Syll. iii. 200. 



Three other species of PhyUosticta are recorded as producing leaf- 

 spots on Paeony. These are PhyUosticta Moutan and PhyUosticta 

 Haldensis in Italy, and PhyUosticta Commonsii in North America. 



Other leaf- spots are produced by species of Septoria, w T ith long thread- 

 like conidia, such as Septoria Pceonice in N.-W. Europe, and Septoria 

 macrospora in Italy. Septoria Martianoffiana is only known in Asiatic 

 Siberia. 



PiEONY Rust. 

 Cronartium Pceonice (Cast.), PI. I. fig. 12. 

 A peculiar kind of rust, not very common but occasionally appearing 

 in gardens, on Pa?ony leaves, chiefly on the under surface, is the above, 

 which has been known for very many years. 



The pustules are small, and collected together on paler spots, but with 

 none of the bright yellow or rusty colour peculiar to most of the plant 

 rusts. 



The uredospores are enclosed in a kind of peridium, or volva, and are 

 dither ovate, or elliptical, and spiny (20 30 x 15-30 fx). From the centre 

 of the spore mass arises a compact column composed of the brown teleuto- 

 spores, or final spores, many of which commence to germinate while still 

 attached to the foster plant. The long rlexuous columns (2 m. long) give 

 a peculiar appearance to this parasite, making it look rather like a colony 

 of worms or L&rvae upon the leaf, commonly extending over a consider- 

 able surface. It has very little of the general appearance of a Uredine, and 

 would rather puzzle the inexperienced. 



It is found throughout the greater part of Europe and in Asiatic 

 Siberia. 



No successful experiments recorded, and the presumable jecidiospores 

 arc unknown. 



