290 BUSH-FRUITS 



berries, so closely does it resemble the tomentum of the leaf. 

 Upon the blackberry its appearance is marked, causing a red dis- 

 coloration of the upper surface of the leaf, as if it were ripening. 

 Halsted calls attention to the fact that this is liable to cause 

 serious trouble to our berry growers, and suggests the advisability 

 of appropriations to stamp out such dangerous species while still 

 confined to limited areas. 



LEAF -BUSTS 

 Phragmidium EuU (Pers.) Winter. Order Uredineae. 



For synonymy, see Sacc. Syll. Fung. 7: 745. Winter, Die Pilze, 1: 230. 

 Burrill, Parasitic Fung., 111., 1: 208. 



On leaves of R. nigrobaccus, and in Europe on R. fruticosus, 

 R. ccesius, R. saxatilis and R. arcticus. 



The uredospore form appears like a coarse dusting of light- 

 colored powder on the under surface of the leaves; the teleuto- 

 spore stage appears in the form of black dots raised above the 

 surface. Although this never seems to have been reported as 

 seriously injurious, the abundance with which it is sometimes 

 found seems to indicate that it might become so. Its position on 

 the under side of the leaves would render it difficult to combat. 



Phragmidium RuU-idcei (Pers.) Karst. 



For synonymy, see Saccardo, Syll. Fung. 7: 748. Winter, Die Pilze, 1: 231. 

 Burrill, Par. Fung. 111. 207. 



On leaves, petioles and peduncles of Rubus Idceus, R. strigosus, 

 R. odoratus, R. parviflorus, R. occidentalis, and R. cuneifolius. 



This is closely related to the preceding species, and is the same 

 in outward appearance; it occurs on raspberries, however, while 

 the other is found chiefly on blackberries. 



SphcBrotheca Humuli (D. C.) Burrill. 



Burrill, Par. Fung. 111. 2: 400. Ellis and Everhart, Pyren. 5. \Erysiphe 

 Humuli, D. C., Flore Francaise, 6: 106. Sphcerotheca Castagnei, Lev. 

 in part. Saccardo, Syll. Fung. 1: 4.] 



Order Pyrenomyceteae. Family Perisporiaceae. 

 Known to occur on leaves of Rubus odoratus, R. triftorus, 

 R. strigosus, R. hispidus, and other species of Rosaceae. 



Treatment. Although not often mentioned as a disease of 



