146 Transactions British Mycological Soctety. 
Again Bailey* has quite recently denied the possibility of a 
“primary”? outbreak of the Hollyhock rust from internal in- 
fection. 
In the absence of a positive proof of the origin of rust on 
seedlings grown under conditions that would forbid all external 
infection, we cannot but conclude that, although Eriksson’s 
researches on cereal rusts have been exceedingly useful, his 
suggestion about their propagation through ‘““mycoplasmic 
symbiosis” does not carry us any nearer to the solution of the 
problem of their recurrence. ; 
3. With reference to the view that infection is carried from 
year to year by means of infected seed, it is interesting to note 
that Pritchardt has sketched definite figures of the mycelium 
of P. graminis inside seedlings from grain that had teleuto-sori 
facing the embryo. He has however not been able to record the 
appearance of any pustules on such plants. Beauverie{ also 
believes in the transmission of rust through infected seed. Re- 
cently Hungerford§, on the strength of elaborate experiments, 
has strongly denied the possibility of the propagation of rust 
from one crop to the next by means of rusted seed grain, and 
so has Eriksson]. 
4. While discussing the importance of intermediate hosts, one 
has to bear in mind the fact that as far as yellow rust is con- 
cerned, no such host has yet been discovered. As regards the 
brown rust of wheat (P. triticina), only recently Jackson and 
Mains] have been able to achieve successful infection of species 
of Thalictrum with its sporidia. 
In the case of black rust too McAlpine** states that in 
Australia the barberry plays no part as an intermediate host, 
the rust being perpetuated from season to season by uredospores. 
Henningt} has also expressed the same view about warm 
countries in general where the barberry does not exist. 
Butlert{ has stated that aecidiospores found on barberry in 
some of the hills could not infect wheat; and has concluded 
therefore that the aecidial stage is of no account in India. 
Pritchard §§ has remarked that the absence of barberry, or its 
* Bailey, M. A., Ann. Bot. xxxIVv, p. 173 (1920). 
+ Pritchard, F. J., Phytopathology, 1, p. 150 (1911). 
+ Beauverie, J., Rev. Gén. Bot. xxv bis, p. 11 (1914). 
§ Hungerford, C. W., Journ. Agr. Res. xIx, p. 257 (1920). 
|| Eriksson, J., Phytopathology, x1, p. 385 (1921). 
{{ Jackson, H. S. and Mains, E. B., Phytopathology, x1, Abstracts, p. 40 
(1921). 
** McAlpine, D., The Rusts of Australia (1906). 
++ Henning, E., Tidsk. f. Landtman, xxv, 1917. Abstract in Hedwigia, 
LXI, p. (49) (1919). 
tt Butler, E. J., Fungi and Disease in Plants (1918). 
§§ Pritchard, F. J., Bot. Gaz. LI, p. 169 (1911). 
