FUNGOID PESTS OF CULTIVATED PLANTS. 59 



menced on some imported plants, and threatened to involve all in 

 destruction. Various experiments were undertaken to check the disease, 

 but proving fruitless the whole of the affected plants were uprooted and 

 destroyed. 



The lower leaves are first attacked and become of a sickly colour. The 

 pustules soon appear upon the leaves, and these split irregularly at the 

 vertex and expose the spores. 



The earliest to make an appearance are the uredospores, which are 

 almost globose (22 x 16 /u) and rough externally. The teleutospores soon 

 follow, which are intermixed with the uredospores in the same pustules, 

 and are larger, of a darker colour, divided transversely into two cells. In 

 form they are somewhat elliptical, each cell being almost triangular, like 

 inverted cones attached at their bases, the lower cell with a colourless 

 stem, which finally disappears (28-38x20-26), the surface quite smooth. 



This pest is reported to be very common in Russia, and not unknown 

 in other parts of Europe. 



As remarked above, all efforts to save infected plants by spraying with 

 fungicides proved to be ineffectual. 



Sacc. Syll. vii. 2153 ; Gard. Chron. Sept. 19, 1885, fig. 82 ; Grevillea, 

 xiv. p. 39 ; Plowr. Brit. Ured. 147. 



PERIWINKLE BUST. 

 Puccinia Vinca (Berk.), PL IV. fig. 72. 



This is a very tenacious species, since when it once attacks a plant it 

 seldom leaves it, making its appearance on the under surface of the 

 leaves. 



A complicated biology is attributed to it, which recognises secidiospores 

 without cluster-cups, but produced in flattened pustules, of a dark brown 

 colour containing globose spores, which are colourless and echinulate 

 (10-12 /i diam.). 



There are also two kinds of uredospores, the primary ones produced 

 early and elongated, the secondary later on and nearly globose. 



The teleutospores are developed normally in small pustules, although 

 an Italian author attempted to establish the fact that there are two kinds 

 of teleutospores, and therefore must be two species of Puccinia, one of 

 which was to be called Puccinia Vinca and the other Puccinia Berkeleyi. 



The teleutospores are elliptical, divided in the centre, and slightly 

 constricted, the upper cell thickened at the -apex, the lower cell some- 

 what attenuated downwards into a long peduncle, which soon falls away. 

 The final spores are rather large (38-56 x 17-28 //). 



Recorded for France, Germany, Portugal, and Italy. 



Sacc. Syll. vii. 2241, 2495 ; Gard. Chron. July 25, 1885, p. 108, figs. 

 22, 23 ; August 20, 1887 ; Cooke M.F. 103, 205, fig. 132 ; Ploivr. Brit. 

 Ured. 161 ; CooJce Hdbk. No. 1478. 



Leaf-spots and a rot-mould are known on the continent of t Europe on 

 the Periwinkle, 



