FUNGOID PESTS OF CULTIVATED PLANTS. 41 



Geranium Leaf-spot. 



We have often seen Pelargonium leaves having large and confluent 

 discoloured and decayed spots, without any evidence of the presence of 

 fungi, hut the spotting has been attributed to sour soil, from which the 

 plants have recovered after a good cleaning of the roots and transplanting 

 in good soil. 



Spots caused on the leaves of uncultivated species of Geranium, such 

 as Septoria Geranii and Rcmularia Gemini, have not been recognised 

 on cultivated species. 



Geranium Rust. 



The leaves of Pelargonium and Geranium have not been free from 

 the attacks of cluster-cups and rusts, but hitherto these have been 

 confined either to uncultivated British or exotic species. Probably ten 

 species of Uredines have been recorded under the several genera, but up 

 to now the leaves of cultivated Pelargoniums have remained free from 

 even an ordinary rust. Uromyccs Gerauii (DC.) is so common, in all its 

 forms of cluster-cup, uredo- and teleuto-spore, upon uncultivated Geranii 

 that it would be prudent to be always on the alert against wild plants in 

 the neighbourhood of gardens. 



In South Africa a Geranium rust (Puccinia granularis) has latterly 

 been causing trouble. 



Tropjeolum Rust. 

 Uredo Tropceoli (Desm.), PL III. fig. 47. 



This rust is by no means common on the leaves of the commonly 

 cultivated Tropwolum, and therefore is not likely to become a pest ; in 

 fact the species of Tropeeolum seem to enjoy a remarkable immunity from 

 the attacks of fungi. 



The pustules are small, and are confined to the under surface of 

 the leaves, over which they are scattered. The uredospor.es are 

 powdery, elliptical, or rarely almost globose, and of a bright orange 

 colour (16 x 10 p.). 



It has been found in France and Belgium, as well as in Britain, 

 but is nowhere common, and hence it is unnecessary to trouble about 

 fungicides. 



Sacc. Syll. vii. 3119 ; Cooke Hdbk. 1578 ; Cooke M. F. 216; Ploivr. 

 Brit. Ured. p. 258. 



Tropjeolum Leaf-spot. 



Pliyllosticta Tropceoli (Sacc). 



This is the only leaf-spot with which we are acquainted upon the 

 leaves of Tropaolum, and this has not been recorded in Britain, but in 

 Italy, Austria, and Portugal. 



The sporules are oblong (6-10 x 3-4 /j) and uncoloured, oozing out 

 when mature from the orifices of the scattered perithecia. 



Sacc. Syll. iii. 212. 



Lupin Rust. 

 Uromyces Anthyllidis (Grev.), PI. III. fig. 48. 

 This rust, with its brand form, occurs not only on the wild Anlhyllis, 



