BY D. McALPINE. i47 



Investigatioxs. 



I have examined a large number of specimens this season from 

 different districts and have found the fungus, as ah^eady stated, 

 on peach, nectarine, plum, apricot and almond. I have also 

 specimens from the Herbarium of the United States Department 

 of Agriculture, through the courtesy of B. T. Galloway, Chief of 

 the Division of Vegetable Pathology, and these may be taken as 

 a starting point. 



On the leaves of Prunu^ americana, the plum of North 

 America (3rd Oct., 1889), there is nothing to be found but two- 

 celled teleutospores, while on the leaves of another species of 

 Prunus (28th Sept., 1889) there are a few uredospores, but the 

 great majority are teleutospores. Fig. 1 shows (a) the uredospore 

 which is yellowish-brown in colour, (6) paraphysis which is of a 

 pale lemon-yellow colour, and (c) teleutospores which are of a 

 dark brown, the lower equallj^^ so with the upper, but in many 

 cases paler. There is no doubt but this fungus is Pnccinia prnni, 

 Pers. In the Victorian specimens the presence of two-celled 

 teleutospores will settle the point that the fungus is not a 

 Uromyces, and the teleutospores are common enough, so that it is 

 a Puccinia. But if the peach leaf is examined in the summer 

 season and even up to July in many cases, onl}^ one kind of spore 

 w^ill 'be found — the uredospore. And even on the plum leaf in 

 the month of March I was unable to find a single teleutospore. 



On the peach leaves sent from Queensland by Mr. Tryon I 

 found both uredospores and teleutospores (figs. 2 and 3). The 

 uredospores were of the normal shape and varying in size from 28 

 to 31 /x long X 14 to 16jLi broad. The teleutospores were also 

 normal, varying from 25 to 34: /^ long x 17 to 20 /x broad, and the 

 pedicels were short and transparent. By gentle pressure the two 

 cells of the teleutospore can be readily separated, and in fact they 

 often fall asunder in the process of mounting. The upper cell 

 seems to be more brittle than the lower, as it is often l^roken up 

 under slight pressure, while the other usually remains intact. I 

 have drawn a lower cell (fig. 2c) separated by gentle pressure, 



