THE AECIDIAL STAGE OF PUCOINIA GRAMINIS PERS. 285 



were takeu from them to inoculate wheat plants and pro- 

 duced typical uredosori. By means of uredospores the 

 British rust is being kept in culture for further study and 

 comparison with Australian forms. 



It was thus shown that the two particulur plants of 

 Berberis vulgaris were susceptible, under the set con- 

 ditions, to sporidia of Puccinia graminis obtained from 

 England. 



(b) Australian Material. 



Numerous unsuccessful attempts were made to obtain 

 viable teleutospores from straw of the 1920-1921 wheat 

 crop; some was kept at the Sydney University and some at 

 the Hawkesbury Agricultural College and forwarded at 

 intervals by Mr. W. M. Came. In September 1921, Mr, 

 L. G. Little, Experimentalist of the Glen Innes Experiment 

 Farm, sent specimens of rusted wheat straw of the 1920- 

 1921 crop which had been harvested in January 1921. Some 

 of the varieties were almost destroyed by the stem rust in 

 this season. Straw of these had been allowed to remain 

 undisturbed on the ground during the winter months, when 

 heavy frosts were frequent. Teleutosori were abundant on 

 the stems and leaf-sheaths. The teleutospores germinated 

 in hanging-drops of tap-water at room temperature (about 

 17 - 20° C). An abundance of sporidia was produced over- 

 night from each sorus. 



On the 29th September and on several occasions during 

 October, inoculations with soaked teleutosori were made 

 on soft young leaves of the same two plants of Berberis 

 vulgaris which had been tested with the British rust. The 

 method of enclosing inoculated shoots in glass cylinders as 

 already described was adopted. The method of merely 

 suspending the rusted straw over the plants was not again 

 tried. 



