FUNGOID PESTS OF CULTIVATED PLANTS. 55 



appear like a different disease, and the ordinary observer might well be 

 puzzled. There is no doubt of its being a prelude or an early stage of 

 the rust ; but it may appear without the rust, and the rust may be seen 

 quite independently of the cluster-cups. 



The cups are usually clustered together on the under surface upon 

 discoloured spots, which are also distinctly indicated on the upper sur- 

 face. The cups are rather urn-shaped, partly immersed, with a white 

 fringed margin. The secidiospores, at first globose, are soon angular, 

 with a roughened surface and yellow (17-23 x 12-18 /x). Of course, 

 as usual, produced in chains within the cups. 



The area of distribution is the same as that of the rust. 



Hitherto cluster-cups have not generally been regarded as trouble- 

 some garden pests, so that picking off and burning diseased leaves has 

 been considered sufficient to prevent spreading. 



Sacc. Syll. vii. 2170 ; Cooke M.F. p. 199 ; Cooke Hdbk. No. 1631 ; 

 Ploicr. Brit. Ured. p. 159. 



Primrose Bust. 

 Pucciuia Primula (DC), PL IV. fig. 70. 



This is one of the species of rust which passes its three stages of 

 cluster-cups, Credo, and Pucciuia upon the leaves of the same plant. 

 Doubtless it is more often met with on wild than on cultivated plants, 

 but its existence is not therefore to be ignored. 



The pustules of the uredospores are aggregated together in some- 

 what orbicular spots, soon splitting the cuticle and setting free the 

 powdery uredospores, which are rounded or ovoid (19-22 ^) and minutely 

 rough on the surface, of a pale brown colour. The pustules are found on 

 the under surface, as well as those of the teleutospores, which latter are 

 scattered or sometimes gregarious, and darker in colour. The teleuto- 

 spores are somewhat elliptical, with a central division into two cells, the 

 upper of which is rounded at the apex and the lower a little narrowed 

 into the very short stem (22-30 x 15-18 /u), externally smooth, brown, 

 with the outer coat thickened at the apex. 



Its distribution is recorded for France, Belgium, Switzerland, Ger- 

 many, and Finland, as well as Britain. 



All the rusts are difficult of treatment, and seldom can be checked to 

 any considerable extent by the use of fungicides. Efforts should be 

 directed rather to check dispersion and extension. 



Sacc. Syll. vii. 2170; Cooke 31. F. 204; Hdbk. No. 1471; Ploior. 

 Brit. Ured. 159. 



Primrose Simple Brand. 

 Uromyces Primula (DC), PI. IV. fig. 69. 



Found on the leaves of Primula intcgrifolia and Auricula, and the 

 theorists have, singularly enough, united this species, as well as Pucciuia 

 Primula, with the Primrose cluster-cups {JEcidium Primula) as the 

 secidiospore form. Hence the one JEcidium must be held to be respon- 

 sible for two species of teleutospores. 



La the present endophyte the teleutospores are elliptical or ovoid 

 (20-35 x 10-20 n) and warted, with a hyaline papilla at the apex and a 



