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THE DESTRUCTIVE AGENTS OF FORESTS. 



Polyporus fissus Berk. 



On maple, Cranberry Glades. 



Trametes robinophila Murr. 



On locust (wounds), Morgantown. 



Tyromyces chioneus (Fr.) Karst. 

 On maple, Sabraton. 



On dead wood, French Creek. (Coll. F. E. Brooks.) 



Pyropolyporus igniarius (L.) Murr. 

 On birch, Cranberry Glades. 

 On maple, Cranesville. 



Pyropolyporus Robiniae Murr. 



On living locust, Sturgisson. 

 On living locust, Elwell. 



Pyropolyporus conchatus (Pers.) Murr. 

 On dead log, Morgantown. 



PyenopoTus cinnabrmus (Jacq.) Karst. 

 On dead wood. Cranberry Mountain. 

 On wild cherry, Reedsville. 

 On wild cherry, Morgantown. 

 On birch, Cranesville. 

 On oak, Morgantown. 



Mildews. 



Erysiphe polygoni. 



On yellow poplar, Morgantown. 



Erysiphe aggregata. 

 On alder, Durbin. 



Podosphaera oxyacanthae. 



On wild cherry, Morgantown. 

 On hawthorn, Cranesville. 

 On hawthorn, Martinsburg. 



Uncinula macrospora Peck. 



On white elm, Ronceverte. 

 On white elm, Point Pleasant. 



Uncinula geniculata. 



On red mulberry, Morgantown. 



Uncinula parvula Ck. & Peck. 

 On hackberry, Martinsburg. 



Uncinula circinata Cooke «& Peck. 

 On sugar maple, Morgantown. 



Microsphaera AIni (DC.) Wint. 

 On birch. Cheat View. 

 On oak, Rohr. 



