82 The Scottish Naturalist. 



ful, the control plants remaining free from the fungus. With 

 sEcidutm Berberidis on wheat, the three experiments performed 

 were all entirely successful, the check-plants remaining free from 

 the fungus. Both the infected and the control-plants in these 

 last-named experiments were raised under bellglasses, and covered 

 by them continuously, except for the few minutes necessary to 

 perform the infection, until the end of the experiment, so that the 

 source of error from accidental atmospheric infection was reduced 

 to a minimum. 



" The culture of Peridermium Pini on the common Groundsel 

 {Senecio vulgaris) has with me been one of the most difficult to 

 perform. After several successive failures, however, I succeeded 

 in two instances in producing the Coleosporium. 



" By the infection of Poa annua with the spores of sEcidiu?n 

 Tussilagiuis, the Pucci?iia Poa rum of Nielsen was in three out of 

 four cultures produced — a Puccinia hitherto unknown in Britain. 



11 Perhaps the most interesting of the series, however, was the 

 production of Aicidium zonale on Inula dysenteiica (also a fungus 

 new to the British flora) by infection with Uromyces Junci. This 

 was successful in every experiment. The actual demonstration of 

 this Hetercecism had not hitherto, I believe, been made, although 

 Fuckel had the strongest ground for believing it to exist. In one 

 of these experiments some fragments of /uncus obtusiflorus, with 

 numerous pustules of Uromyces, in active germination, on them, 

 were placed upon the upper leaves of a plant of Inula dysenterica; 

 in the course of ten or fifteen days these leaves began to show the 

 yellow spots, which were the forerunners of the sEcidium. By 

 his time the plant had grown taller, and had developed fresh 

 leaves above those on which the Juncus had been placed. The 

 fragments of Juncus were then removed from the leaves, on which 

 they had been in the first instance placed, to the healthy, recently 

 expanded leaves above, where in due course the sEcidium was de- 

 veloped. It was very interesting to observe how the &cidium 

 could thus be produced in successive crops." 



In the article from which the above quotations are taken 

 {Grevillea, Vol. XL, pp. 52-57), the details of these experiments 

 are described, from which it appears that the fungus showed signs 

 of its presence often in a few days, and usually became fully 

 formed in from one to two months after infection of the host- 

 plant. .In the same paper are described similar experiments, with 

 a like result, made on Puccinia Caricis and ^Ecidium Urticce, the 

 Puccinia spores off Car ex hirta causing the appearance of jEc. 

 Urticai on Urtica dioica, and conversely the JEcidhan spores so 

 produced, when laid on C. hirta giving rise to Uredo Caricis on it : 

 on Puc. Magnusiaua and jEc. Rumicis ; Kumex Hydrolapathum, 

 infected with Puccinia from leaves of Phragmi/es communis pro- 

 ducing jHc. Rumicis (the same treatment of Rumex obtusifolius 

 produced no result) ; and on *-Ec. R/iamni and Puc. cjtonata, 



