134 258 Mycologia 



6. Puccinia Seymouriana Arth. (Aecidium obesum Arth.). 

 This rust on Spartina at the time it was described in 1902 was 

 predicted upon morphological and geographical grounds to have 

 its alternate form upon the Rubiaceous genus Cephalanthus, 1 * the 

 prediction being established by cultures in 1905, and confirmed 

 in subsequent seasons. 15 It was not until June, 19 13, that addi- 

 tional suggestions came to light, when Rev. J. M. Bates wrote that 

 his observations in the field led him to believe that in Nebraska 

 this rust on Spartina was connected with an Aecidium on Apo- 

 cynum hypericifolium. He sent a specimen of the aecia, which 

 proved to be Aecidium obesum Arth. This collection was distrib- 

 uted as 4103 of Barth. Fungi Columbiani, and 1301 of Barth. N. 

 Amer. Ured. Later in the year a careful microscopic comparison 

 of these aecia with those on Cephalanthus established their essen- 

 tial similarity. Owing to adverse seasonal conditions Mr. Bates 

 was unable to supply culture material for the 1914 cultures, but 

 on May 8, 191 5, he sent telial material on Spartina Michauxiana 

 from Eight Mile Creek, near Red Cloud, Neb. It was sown May 

 12, on Apocynum cannabinum, Amsonia salicifolia, Asclepias syri- 

 aca, and Cephalanthus occidentalis, producing a scanty infection 

 only on Apocynum, pycnia showing June 10, but without develop- 

 ing aecia. 



A specimen of aecia on Asclepias pulchra, collected by Mr. Roy 

 Latham, of Orient, N. Y., June 29, 1914, was reported to the 

 collector upon cursory examination only, as aecia of Puccinia 

 Jamcsiana, that being the only species at that time known to have 

 aecia with a limited mycelium on Asclepias, and it was suggested 

 that he search for telial material on Bouteloua. Not long after- 

 ward he wrote that Bouteloua was not known upon Long Island, 

 and that among the infected milkweeds, which occur on " a patch 

 about 100 feet in length by 25 in width, many plants being actually 

 covered from ground up, stem, leaves, and all," the only grass or 

 sedge bearing rustwasSpartinacynosuroides,oi which he sent leaves 

 covered thickly with telia remaining over from the preceding year, 

 and young leaves of the season with uredinia. The Spartina rust 



i^Bot. Gaz. 34: 13. 1902. 



!5 Jour. Myc. 12:24. 1906; Mycol. 1:236. 1909; 4: 19. 1910. 



