198 



Mycologia 



Mr. W. P. Fraser^^ of Pictou, Nova Scotia, when he made sow- 

 ings in the spring of 1910 of tehospores of Uromyces Peckianus 

 Farlow on Atriplex patula and Cheno podium album, both of 

 which produced infection and formed aecia of the same type as 

 those of Puccinia suhnitens Diet, on the same hosts. This ex- 

 tremely interesting result led to a careful comparison of the two 

 rusts with results as follows : Puccinia suhnitens Diet., is a rust on 

 Distichlis spictata (L.) Greene and has its aecia on a large num- 

 ber of Chenopodiaceous, Capparidaceous and Cruciferous hosts,^® 

 which include Atriplex, Beta, Cleome, Capsella, Chenopodium, 

 Lepidium, Sarcohatus, etc. The aecia are grouped and have erect 

 peridia with peridial cells rhomboidal and in radial sections much 

 thickened in the outer wall. On comparing the aecia of Uromyces 

 Peckianus it was found that they were identical in all discernible 

 morphological characters. The chief interest, however, lies in 

 a comparison of the urediniospores, the morphology of which has 

 been of greatest use in the study of the grass and sedge rusts. 

 The urediniospores of Puccinia suhnitens measure 18-24 by 19- 

 26 jn, are pale cinnamon-brown with a wall about 2 /x thick, very 

 finely verrucose, the pores 6, scattered. The urediniospores of 

 Uromyces Peckianus measure 16-21 by 18-24 /x, are pale cinna- 

 mon-brown with a wall about 2.5 ^ thick, very finely verrucose, 

 and have 6 scattered pores. The tehospores of the two rusts pos- 

 sess no differential characters except, of course, number of cells 

 and consequent size. 



The distribution of the two is interesting. The telial host of 

 both, Distichlis spicata (L.) Greene, grows in salt marshes on the 

 Atlantic and Pacific coasts and in saline soil in the interior. 

 Uromyces Peckianus is known only from the coastal regions while 

 Puccinia suhnitens on the other hand is an interior form having 

 been collected at only one point on the coast and that at Lewes, 

 Delaware. The reason for this is speculative at present, but it 

 seems probable that the one-celled form is less adaptive to varying 

 conditions of soil and temperature than the two-celled form and 

 so has thus far been unable to thrive in the interior, 



"Mycologia 3: 72-74. 1911. 



" Bot. Gaz. 35: 19. 1903; Jour. Myc. ii: 55. 1905; 12: 16. 1906; 13: 197. 

 1907; 14: 15. 1908; Mycologia i: 234. 1909; 2: 225, 1910: 4: 18. 1912; 4: 54. 

 1912. 



