Hedgcock: Notes on Western Uredineae 147 



9. Uredo (Melampsora) bigelowii (Thiim.) Arth. 



The aecial form of this rust on larches has not been collected 

 as yet by the writer in the national forests, but it may be common, 

 and if search were made at the right season, it might be found. 

 The uredinial and telial forms are found on nearly every species 

 of willow in the west and southwest, not only where larches are 

 found, but where there are none within a thousand miles. It 

 has been collected on the following species of Salix: Salix amyg- 

 daloides Anderss., S. bebbiana Sarg., S. cor data lutea (Nutt.) 

 Bebb., S. cordata mackenziana Hook., vS. fluviatilis Nutt., S. 

 laevigata Bebb., vS. lasiandra Benth., vS. lasiandra caudata (Nutt.) 

 Sudw., vS'. lucida Muehl., vS. nigra Marsh., 6". nuttalii Sarg., and 

 vS. sessi folia Nutt. 



The telial form of the fungus fruits so abundantly on some 

 species as to exert a decidedly stunting effect. On the willows 

 cultivated by the Forest Service near Washington, D. C, for 

 experiments in making baskets, it is a serious parasite. 



10. Uredo (Melampsora) medusae (Thiim.) Arth. 



Species of poplar are commonly attacked by the uredinial and 

 telial forms of this rust, but the aecial forms, supposedly on 

 larches, have not been found. It has been collected on the fol- 

 lowing species of trees: Populus acuminata Rydb., P. angusti- 

 folia James, P. balsamifera L., P. grandidentata Michx., P. 

 tremuloides Michx., and P. trichocarpa Torr. & Gr., chiefly in 

 the west and northwest. It occurs so abundantly on some species 

 as P. acuminata and P. trichocarpa, that it injures the leaves and 

 arrests the growth of younger trees. 



Office of Investigations in Forest Pathology, 

 Bureau of Plant Industry, 

 Washington, D. C. 



