538 MINNESOTA BOTANICAL STUDIES. 



In Sargent's Sylva* is a statement that pines are sometimes sub- 

 ject to the distortions known as witches' brooms. Dr. Farlow 

 writes, however, that this statement was based on a reported 

 witches' broom on Pinus -ponderosa from Montana and that 

 further study of the material demonstrated that the distortions 

 were not typical witches' brooms, nor were they caused by a 

 fungus parasite. No definite statement as to the cause of the 

 broom of white pine collected in Minnesota can be made until 

 older material is obtained and a more detailed description is 

 therefore deferred. 



DESCRIPTION OF PLATE XXXII. 



Witches' broom on Pinus strobus, Mille Lacs county, Minn. After 

 photograph by R. S. Mackintosh, May, 1900. 



I. MELAMPSORACE^E. 



Chrysomyxa UNGER. 



One species of this genus has been found. Common on 

 Pyrolas throughout the State. 



i. C. pirolatum (KOERN.) WINT. Die Pilze i 1 : 250. 1884. 

 On leaves of : 



Pyrola rotundifolia L. : Goodhue, (II) Je. 1893, Ballard ; 



Freeborn, (II) My. 1891, Sheldon 5964 and 5963. 

 Pyrola elliptica. NUTT. : Aitken, (II) Je. 1892, Sheldon 

 2101 ; Houston, (II) Je. 1899, Lyon 98; Mille Lacs, (II) 

 My. 1900, H. B. Carey and Freeman 560. 

 Pyrola secunda L. : St. Louis, (II) Jy. 1886, Hoi way 27. 

 [ Urcdo pyrolcs (Gm.) Wint.j 



Cronartium FRIES. 



Not yet collected by the survey staff, but one species has been 

 reported by Seymour. 



i. C. asclepiadeum (WILLD.) FR. Obs. Myc. i: 220. 1815. 

 Var. quercuum B. & C. 



Crow Wing, (III) Ag. 1884, Seymour. (Economic Fungi. 

 A. B. Seymour and F. S. Earle, No. 215.) 



Coleosporium LEVEILLE. 



One species found. Very abundant throughout the State. 

 Uredospore form most abundant and conspicuous. Only one 

 collection of the teleutospores has been made. 



*Svlva of N. A. ii : 12. 



