Rust of Brontes {Puccini a dispersa). 489 
Ward is undoubtedly due to this cause. The rainfall though 
not excessive was evenly distributed, and sunshine less than 
normal throughout. The drying up of the infected leaves, 
though, in all probability, usually accelerated by the action of 
the Fungus, was in many cases due largely to severe weather 
conditions. 
The results confirm in general those obtained by Marshall 
Ward, but under different seasonal conditions. The success 
of the infections under the unfavourable conditions encountered 
adds interest to the result, since it accentuates the possibility 
of natural field infections throughout the winter season. The 
following is merely an account of the experiments ; the 
bearing of the results will, it is hoped, be more fully discussed 
in a future paper by Professor Marshall Ward. 
The following tables sum up the results obtained during 
the progress of the experiments. The column f host ’ includes 
the species upon which infections were made ; then follow the 
species from which the brown rust spores were taken, viz. 
B. mollis and B. sterilis. About one half of the plants in 
each pot were infected and their position marked, so that the 
control and host plants could later be distinguished. This is 
of some importance, as in Experiment 94 g l , although five of 
ten plants were infected and five plants subsequently bore 
pustules, two of the pustules were on control plants and not 
due to the artificial infection unless accidental as indicated 
above. The germination of the spores in distilled water after 
twenty-four to forty-eight hours was classified as c very poor ’ 
when only a few tubes can be found in the watch-glass ; as 
* excellent ’ when there are only a few spores which do not 
germinate. The intermediate conditions are self-explanatory. 
Records were kept of experiments in which all of the spore 
material was taken from the same leaf; and the numbers in 
the columns under the various dates indicate the number of 
plants whose infected leaves produced one or more pustules 
of brown rust. 
The formation of yellow flecks in the leaves, which often 
1 See footnote, p. 488. 
