Fraser: Cultures of Heteroecious Rusts 187 



and aecia on June 27, also in abundance. Another sowing on 

 June 27 gave pycnia on July 7 and aecia on July 16, but not in such 

 abundance, probably owing to the maturity of the leaves. Three 

 different sowings were made on Spergularia canadensis and one 

 each on Stellaria media (L.) CyrilL, S. graminea L., and Glaux 

 maritima L. without infection in any case. 



Teliosporic material from Spartina glabra var. alterniflora was 

 sown on Spergularia canadensis on June 12 with pycnia on June 

 20 and aecia on June 27. A previous sowing on the same host 

 was successful, but the dates were not kept. Two sowings were 

 made on Arenaria lateriflora without infection. 



A sowing of teliosporic material from Spartina patens was 

 made on Spergidaria canadensis on June 12 with pycnia on June 

 20 and aecia on June 27. Two further sowings made, one on 

 June 27 and the other on the 28th, were also successful, producing 

 pycnia and aecia in due time. Two sowings were made on Are- 

 naria lateriflora and one on Salicornia europea without infection. 



The field observations and cultures show that Uromyces Spar- 

 tinae on Spartina Michauxiana has aecia on Arenaria lateriflora 

 but not on Spergularia canadensis, v\^hile the same rust on S. 

 patens and S. glabra var. alterniflora has aecia on Spergidaria 

 canadensis and not on Arenaria lateriflora. 



Dr. Arthur studied the field collections and culture material here 

 described for vol. 7, part 3, of North American Flora, which 

 includes this species. His conclusions in regard to the position 

 of this species can be gathered from his treatment of it in that 

 work. 



Melampsora arctica Rostr. 



A species of Caeoma was found to occur abundantly on Abies 

 balsamea during the early summer of 1910. A collection of the 

 material was sent to Dr. Arthur, who suggested that it might be 

 the aecial stage of Melampsora arctica Rostr. Field study con- 

 firmed this suggestion, as the willows in the neighborhood of the 

 Caeoma soon developed uredinia and telia of Melampsora artica 

 Rostr. Leaves with telia were collected in the fall and v^intered 

 and the teliospores gave good germination in a few days in a 

 moist chamber. A sowing was made on Abies balsamea on May 



