The Plum-Rust in England. 
207 
THE LIFE-HISTORY OF THE PLUM-RUST IN ENGLAND. 
By F. T. Brooks, M.A. 
(The Botany School, Cambridge). 
NTIL recently it was not known whether an aecidial stage was 
present in the life-cycle of the Plum-Rust, Puccinia Pruni f 
Pers., but in 1904 Tranzschel, 1 working in Russia, shewed that 
TEcidium punctatum on Anemone coronaria was the alternate phase 
of this fungus. More recently still, Arthur 2 in the United States has 
confirmed the heteroecismofthe Plum-Rust by proving experimentally 
that the aecidium on Hepatica acutiloba —a plant very closely allied 
to Anemone coronaria, is a stage in the life-cycle of this fungus. 
JEcidium punctatum occurs on Anemone coronaria in England 
and the Rust on Plum leaves is becoming more common year by 
year in fruit-growing districts, but as far as I am aware no experi¬ 
ments have hitherto been performed to see whether thisaecidium is 
a stage in the life-cycle of the Plum-Rust as it occurs in this 
country. It is important that this should be done because it is 
becoming more and more recognised that the life-histories of Rust- 
Fungi, especially the heteroecious species, should be worked out for 
each country separately. 
Towards the end of April some material of ALcidium punctatum 
growing on Anemone coronaria in the neighbourhood of Cambridge 
was brought to me by Mr. Laidlaw, a student working in the Botany 
School, so it was thought desirable to ascertain if Plum-Rust could 
be induced by placing these aecidiospores on the leaves of a healthy 
Plum-tree. For this purpose a young “Victoria” Plum-tree was 
selected because this variety of Plum is particularly susceptible to 
attacks of Plum-Rust in this district. The Plum-tree was established 
in a large pot and fresh aecidiospores from the affected Anemones 
were placed on the upper and lower surfaces of a number of leaves, 
the whole plant being enclosed in a bell jar after the inoculations 
had been made. Certain leaves were left uninoculated as controls. 
Three weeks later, twenty-three of the leaves thus inoculated were 
found to bear on their under surface uredo pustules of the Plum- 
Rust, whereas the control leaves shewed no sign of the Rust. It is 
thus clear that JEcidium punctatum is a stage in the life-history of 
1 Tranzschel, W. : Arbeit, der Kais. St. Petersburg, Nat. Ges., 
1904. 
2 Quoted in Duggar’s “ Fungous Diseases of Plants,” p. 418, 
