Notes on the Weymouth- Pine Rust ' 367 



NOTES ON THE WEYMOUTH-PINE RUST. 



Opportunities have occurred at Haslemere during the last 

 five years for some observations, of considerable interest, in 

 reference to the fungus which causes this disease. The attack 

 occurred almost exclusively in the first year of this series, and 

 during the latter term only its results have been displayed. 

 There has been no fresh prevalence. The following notes 

 record the chief facts, amongst which may be mentioned the 

 recognition for the first time in Britain of the Tubercularia 

 maxima as a parasite upon the Peridermium. 



The loan of a block, courteously afforded by the pub- 

 lishers of Mr. Massee's book (which we review at p. 370), 

 enables us to- offer an illustration of the fungus in its different 

 forms. 



In 1901 this disease was very prevalent at Haslemere; 

 many Weymouth-pines in the district were damaged, and 

 a few were killed. At Inval, where it was first observed in 

 May, the crowns of the trees suffered severely, but many of 

 the lower branches were also affected. The needles drooped 

 and withered. At the base, or near it, of each infected 

 branch, were found the pale yellow cups (aecidia) of the Peri- 

 dermium strobi. These are shown, natural size, in fig. 5. 



There was associated with these, in most cases, a purplish 

 fungus which it was difficult to determine. Specimens were 

 sent to Kew for identification, and were there recognised as the 

 Tubercularia maxima, a parasite of the Peridermium hitherto 

 not observed in this country. The aecidia of the Peridermium 

 contain orange spores. Two of these, highly magnified, are 

 shown in fig. 6. During the first season of the attack aecidia 

 are not formed, only spermogonia. These contain spermatia, 

 minute flask-shaped bodies seated on the tips of delicate 

 threads (hyphae) which spring from the inner basal surface of 

 the spermogonium. The significance of these bodies is not 

 properly understood, but they are now considered by many to 

 be effete male organs. The aecidia appear in the second year. 



