26 FUNGOID PESTS OF CULTIVATED PLANTS. 



The present is a widely diffused species, and is known, not only in 

 Britain, but also in France, Belgium, Germany, Switzerland, Italy, 

 Austria, Finland, Asiatic Siberia, North America, and Patagonia. 



It is doubtful whether fungicides are of much service with such deeply 

 seated endophytes as Puccinia, although it was affirmed, during the 

 greatest prevalence of the Hollyhock Puccinia, that spraying with Condy's 

 fluid was decidedly advantageous. 



Sacc. Syll. vii. 2163 ; Cooke M. F. 102, 210 ; Plowr. Brit. Ured. 152 ; 

 Cooke Hdbk. No. 1502. 



It should be mentioned here that another species of rust has been 

 found, in Britain and Germany, on the leaves of Viola palustris, and 

 named Puccinia Fergussonii, in which the pustules are clustered together 

 in large rounded patches. The teleutospores are smooth and rather 

 deformed (20-30 x 13-20 //) ; no uredo spores have at present been found 

 (Grevillea, iii. p. 179). 



Yet another species (Puccinia hastata) occurs on the leaves of 

 Viola hastata in the United States, with much larger teleutospores 

 (35-40 x 20-25 /i) and smooth globose uredospores. 



A third species (Puccinia alpina) is found on leaves of Viola biflora 

 in Germany, Switzerland, Italy, and Lapland. The teleutospores are 

 longer than in any other of the species (30-52 x 17-23 /<), with the surface 

 finely granulated. 



VIOLET CLUSTER-CUPS. 

 MMium Viola (Schum.), PI. I. fig. 21. 



In these modern days the above cluster-cups are treated as a stage in 

 the development of Puccinia Viola, but their general appearance is so 

 distinct that for general purposes we prefer to treat them as a separate 

 disease. 



All the green parts of the Violet plants are liable to be invaded by 

 this parasite. The cups are disposed in groups or clusters, seated on 

 the leaves upon yellowish spots. The margin of the cup is white and 

 torn into irregular teeth, exposing the bright orange aecidiospores (16-24 

 x 10-18 fj), which, as usual, are produced in chains, being separated and 

 dispersed when mature. 



The area of distribution corresponds with that of the Violet rust. 



It is not sufficiently common to have originated any experiments with 

 fungicides. 



SCATTERED CLUSTER-CUPS. 

 Puccinia cegra (Grove), PL II. fig. 22. 



Another species of cluster cups was discovered in 1876, principally on 

 the stems, but also on the foliage of Viola cornuta. The cups are few 

 and scattered (Mcidium depauperans) and the aecidiospores are also 

 orange. In 1883 the corresponding Uredo and Puccinia were found, 

 which were described under the name of Puccinia agra. They have 

 hitherto only been found in Britain (Grevillea, v. p. 57). 



A species of cluster-cups has also been found on wild Violets in the 

 United States. 



