Cultures of Uredineae in 1916 and 1917 295 



sporic Car ex rust, Puccinia micros or a Korn., was searched for 

 clues to the alternate host without much success. A twelve- 

 mile ride in another direction to Bear Meadow, an extensive 

 mountain bog, gave opportunity to study the occurrence of P. 

 uniporula, and some other difficult Carex forms. 



On May 13 a western trip of a little over three weeks was 

 begun. The first stop was a few days given to the study of 

 the rust flora of the semi-arid plains between Grant and Ogallala 

 in western Nebraska, where the second telial host for Puccinia 

 universalis to be proven by cultures was found. 



Next came a few days (May 18-22) at Laramie, Wyo., altitude 

 of 7,500 feet, where the season was not sufficiently advanced for 

 the best field work, but where through the courtesy of Professor 

 Aven Nelson and the assistance of Mr. Edwin Payson an exami- 

 nation of the extensive and valuable Rocky Mountain Herbarium 

 yielded many new hosts and localities for numerous western 

 rusts. 



Interesting observations were made (May 23-24) in the vicinity 

 of Ft. Collins, Colo., where every attention was extended by 

 members of the biological staff of the Agricultural College. Pro- 

 fessor W. W. Robbins undertook to continue the observation of 

 a number of clumps of Astragalus and Oxytropis as the season 

 advanced. These plants were growing with masses of aecia- 

 bearing Euphorbia robusta intermixed. On October 24 Pro- 

 fessor Robbins reported that no rust had appeared on any of the 

 plants of Astragalus or Oxytropis under observation. From 

 European studies it has seemed probable that the perennial aecia 

 on upright Euphorbias and the Uromyces punctatus on Astragalus 

 and allied hosts, both especially abundant in the Rocky Moun- 

 tains, were alternating forms of the same rust, but so far neither 

 repeated attempts at cultures nor field evidence have afforded any 

 support to the assumption. 



At Windsor, Colo., as the guest of Mr. Geo. E. Osterhout 

 (May 25), a fine display of over-wintered Puccinia Distichlidis 

 on Spartina was seen in the field with an abundant growth of 

 Stieronema ciliatum nearby. Telial material from this locality 

 subsequently gave successful cultures, and on June 12 Mr. Oster- 

 hout sent aecia on Stieronema, which he obtained from the spot 



