70 229 Mycologia 



May 27; also sown same date on Euthamia graminifolia, showing 

 pycnia May 22, at aecia June 4. 



The significant thing about these cultures is that the material 

 from Carex scoparia, which was sent by Mr. W. P. Fraser, grew 

 on both Aster and Euthamia. The rust on this species of Carex, 

 as represented in the herbarium, was for a long time considered 

 sufficiently diverse morphologically to constitute a distinct spe- 

 cies. Two years ago material on Carex scoparia from Maine was 

 cultured on Euthamia, 10 but did not grow on Aster paniculatus 

 or Solidago canadensis. This year sowings were made on the 

 three hosts named and results obtained on two of them. It was 

 pointed out in the discussion of the results two years ago that the 

 Aster-Solidago-Erigcron group of Carex rusts probably consti- 

 tutes a single species with a number of more or less defined races. 

 The same view has been expressed elsewhere. 11 Numerous con- 

 firmatory facts of diverse nature have been accumulating, until it 

 seems advisable to adjust the nomenclature to accord with present 

 knowledge. 



This species is one of the most common forms of rust in North 

 America. It evidently is less abundant in South America and 

 in the eastern hemisphere. The morphological study of similar 

 European forms, rated as species, discloses some that undoubt- 

 edly are to be classed in the same category with the American 

 group. Without taking space to record the evidence, the con- 

 clusion has been reached that the most available name for the 

 American and European constituents of the species here repre- 

 sented, but possibly not the oldest one, is Puccinia extensicola 

 Plowr. This name was founded on telial material from Carex 

 extensa, obtained at Norfolk, England, and cultured on Aster 

 Tripoli, and is in every way comparable with the Carex- Aster 

 forms of America. 12 



3. Puccinia angustata Peck. Teliospores on Scirpus atro- 

 virens, collected at Lafayette, Ind., by L. O. Overholts, were sown 



10 Mycol. 4: 15. 1912. 



11 Arthur, The physiologic aspect of the species question. Amer. Nat. 

 42 : 246. 1908. 



12 For previous American cultures of this specific group, see Bot. Gaz. 

 35 : 15, 21. 1903 : Jour. Myc. 8 : 53, 54. 1902 ; 11 : 58. 1905 : 12 : 15. 1906 ; 

 14: 13. 1908; Mycol. 1: 233. 1909; 2: 224. 1910; and 4: 15, 16. 1912. 



