Davis — Parasitic Fungi in Wisconsin — HI. 261 



Vredinopsis atkinsonii Magn. Primary uredinia and telia on 

 Aspidium noveboracense. St. Croix Falls. 



In the provisional list no aecia on Pinus were recorded save an 

 undetermined Peridermium on leaves of Pinus Banksiana. This 

 was not because of the absence of such rust forms from the state, 

 but because field work had not been done in the proper regions 

 at the proper time to detect them. Since the list was prepared, 

 however, some attention has been given them, the results of which 

 it may be of interest to summarize. 



The leaf Peridermium on Pinus Banksiana was collected in 

 July 1907, near Gordon, Douglas County, and at Spooner, Wash- 

 burn County. It is presumably connected with Coleosporium 

 but has not been observed since. Peridermium cerebrum Pk. 

 occurs throughout the range of Pinus Banksiana in the state and 

 is quite abundant in some localities. Its effects are serious only 

 when the infections are multiple or when it attacks the axis. 

 The distribution of Peridermium pyriforme Pk. is also probably 

 coextensive with the range of Pinus Banksiana in the state it 

 having been collected in Jackson, Douglas and Vilas Counties, 

 but it appears to be very sparsely distributed. In June, 1914, 

 when special attention was given to it, no more than one speci- 

 men was collected in any locality. If this is connected with 

 Cronartium comandrae Arth. it is not nearly so abundant or 

 widespread as the telial form. Peridermium comptoniae Orton 

 & Adams on the contrary, while it has been observed only in 

 Douglas and Vilas Counties, occurs in considerable abundance 

 both as to number of trees attacked and the extent of the out- 

 break on the individual tree. As I have seen it this usually oc- 

 curs on the trunk near the base while Peridermium pyriforme 

 Pk. I have seen only on branches. This is contrary to the state- 

 ment of Arthur & Kern (Mycologia 6:132). Besides its native 

 host, Pinus Banksiana, this rust attacked the young trees of Pi- 

 nus ponder osa in the plantation of the Board of Forestry in 

 Vilas County with severity; a severity due in large measure, 

 doubtless, to the fact that the rust does not occur in the native 

 habitat of this host and hence there has been no breeding out of 

 susceptibility. Of the European Peridermium fischeri Kleb. 

 which became thoroughly established on Pinus sylvestris in Door 

 County, I have written elsewhere. It is hoped that with the de- 

 struction of the alternate host, Sonchus, this will disappear from 



