CALYPTOSPORA GOEPPERTIANA 59 



side in crowded patches ; they are brown and unicellular. They 

 are not perfectly ripe till the following April ; then, if the leaves 

 are gathered from the forest-floor where they have lain all the 

 winter, brought into a room and kept moist, the teleutospores 

 will germinate in great numbers by sending out basidia in the 

 usual way, though it is not possible to discern a germ-pore in 

 the ungerminated spore. The basidiospores in turn infect the 

 Pine, and the cycle begins again. 



In the Aspen the mycelium affects only the leaves and 

 causes little harm, since the leaves do not fall off prematurely : 

 in the allied species, Melampsora Rostrupii, I have found the 

 root-suckers round the parent tree to be most infested at first. 

 Besides P. tremula, the Abele Poplar (P. alba) is also able to 

 propagate the disease, as well as the hybrid between them, 

 P. alba x tremula. The chief harm is done to the Pines : 

 Hartig showed that seedling pines are often killed by an attack, 

 but if the tree manages to survive over thirteen years it may 

 recover. In any case the tree is more or less spoilt by the 

 distorted and dead branches, and, if it is true that the aecidio- 

 spores can spread the disease on the pines, it is evident that 

 young seedlings, when seen to be infested, should be pulled up 

 and burnt at once. Another precaution suggested by the life- 

 history is not to allow plantations of the two species of poplar 

 near to a seed-bed of Scots Pine. 



It must be remembered that there are several other 

 Uredinales on Pinus silvestris, and also others on the Aspen 

 which have no connection with Melampsora pinitorqua : the 

 latter species can be easily recognised by the curvature of the 

 young pine-branches, which is not produced by any of the 

 others. Fortunately the disease is rare in this country, as in 

 many other countries. 



Calyptospora Goeppertiana. 



The Cowberry and Silver Fir Rust. 



This fungus produces its teleutospores on the Cowberry 

 (Vacdnium Vitis-idaea), and its secidiospores chiefly on the 

 Silver Fir ( Abies pectinata) : it has no uredospores. 



