1911-12.] BOTANICAL SOCIETY OF EDINBURGH 11 



Weymouth pine has been introduced into America, the 

 home of Pin v.* strobus, with a consignment of seedling- 

 from Hamburg. In America the disease was unknown and 

 had never been seen there on native trees. Every pre- 

 caution has been taken to prevent the spread of the 

 •disease, and it is hoped that this invasion may be repulsed 

 as a previous appearance of the disease in Xew York in 

 1906 was immediately stamped out. 



" It is difficult to understand why America imports 

 seedlings of Pinus strobus in spite of all European 

 experience and warning, instead of supplying her own 

 want^ by seedlings raised from native seeds." 



Here is a remarkable example : — An American tree is 

 introduced into Europe, becomes the victim of a European 

 fungus, and in course of time young diseased plants are 

 sent from Europe to America, to the imminent danger of 

 the indigenous trees. The loss to America would have 

 been great if she had not had an organised department to 

 arrest and quarantine these infected plants even at the 

 eleventh hour. 



The Weymouth pine is a very desirable tree to grow, 

 not only arboriculturally for ornamental purposes, but also 

 sylviculturally for the sake of its timber. It is called 

 White pine in America, but on this side of the Atlantic its 

 timber is known as Yellow pine, a kind of timber which 

 has become very scarce and expensive of late years, owing 

 to its having been too severely exploited in America. I 

 have seen this tree growing well in the south of England, 

 where it gave every promise of forming an excellent stand 

 of timber in a comparatively short rotation, but I also 

 noticed traces of this disease in its neighbourhood. In 

 Scotland the Weymouth pine grows quite well in suitable 

 places, but the disease is unfortunately rampantly epidemic. 



The fungus belongs to the group of metoxenous forms, it- 

 alternative host being almost every .-pedes of R: 

 certainly R. nigrv/m, Pi. alpinum, P. awreum, and 

 P. grossularia. This fungus is doubly injurious, since it 

 attacks two host plants of economic importance. No 

 effort should therefore be spared to prevent the further 

 spread of this disease or to stamp it out, and such is not 

 beyond the power of properly organised practical mycology. 



