Fraser: Cultures of Heteroecious Rusts 177 



angustifolmm L. on June 14 and the uredinia of Pucciniastrum 

 pustulatum were noticed about two weeks later. 



In the field where the telia for the culture were collected, a few 

 trees of Abies balsamea grew among the rusted Epilohium. 

 These were watched for the appearance of pycnia and aecia and 

 the first collection was made on June 19, when the pycnia were 

 well developed but the aecia were not mature. Several collec- 

 tions were made later but the aecia were few considering the 

 abundance of the telia and the fact that all tested in the labora- 

 tory gave excellent germination. Probably the scant development 

 was due to the very dry weather that prevailed during IMay and 

 June until the leaves of the host were too old to be readily in- 

 fected. In the laboratory tests, at least four days in a moist 

 chamber were necessary for the germination of the teliospores. 



European investigators have shown that the aecial stage of this 

 rust is on Abies pectinata DC, but as far as the writer is aware 

 these are the first experiments with American material and the 

 first collection of aecia in North America. 



Calyptospora columnaris (A. & S.) Kuhn 



The swollen stems of Vaccinium pennsyhanicum Lam. bear- 

 ing the telial stage of this rust were placed in a moist chamber 

 on May 12 and the teliospores were germinating freely by May 

 17. A young plant of Abies balsamea (L.) Mill, was then in- 

 fected on the latter date in the usual way. Aecia were first 

 noticed appearing on June 3 and were mature by June 12. There 

 was no trace of pycnia. An attempt was made to infect Tsuga 

 canadensis (L.) Carr., but without success. 



In the field, aecia began to appear during the last week of June 

 and were abundant on the host in this region {Abies balsamea) 

 during the first and second weeks of July. 



Arthur (Mycol. 2 : 231. 1910) infected Abies Fraseri (Pursh) 

 Poir, using telial material from this region. This is the only pre- 

 vious culture with North American material. 



Melampsoropsis ledicola (Peck) Arthur 



Teliosporic material of this rust on Ledum groenlandicum 

 Oeder was sown on Picea canadensis (Mill.) BSP. on June 5. 



