218 



Mycologia 



During the present season 178 collections of material with 

 resting spores and 18 collections with active spores were em- 

 ployed, from which 684 drop cultures were made to test the 

 germinating condition of the spores. Out of the 178 collections 

 with resting spores 95 could not be brought to germination, leav- 

 ing 83 collections of available material to serve for the projected 

 cultures. These 83 collections with resting spores and 18 with 

 active spores belonged to about 70 species of rusts. Altogether 

 345 sowings were made, employing for the purpose 97 species 

 of hosts, these being grown in pots. 



The results of this work are given in the following' para- 

 graphs, and are divided into negative results, positive results 

 with species whose life cycles have already been ascertained by 

 the writer or other investigators, and positive results with species 

 whose life cycles are now first completed and placed on record. 



Negative results : — Quite a number of collections gave good 

 germination of the spores, and these were sown on plants in the 

 hope of discovering the alternate host, but no infections were 

 secured. The following may be recorded to serve for reference 

 in future studies, although not so much importance can be 

 attached to these results as in former years, owing to unsatis- 

 factory conditions, as stated above : 



1. PucciNiA on Care.v tenella Schk., collected at Pictou, Nova 

 Scotia, by Prof. W. P. Fraser, was sown on Boehmeria cylindrica, 

 Apocymim cannahinum, Lepargyraea canadensis, Syniphoricarpos 

 paucifloriis, Rudheckia laciniata and Iva frutescens, with no in- 

 fection. 



2. PucciNiA on Carex tennis Rudge, collected at Pictou, Nova 

 Scotia, by Prof. W. P. Fraser, was sown on Aster paniculatus, 

 Solidago canadensis, Erigeron annuus, Onagra biennis and 

 Ambrosia trifida, with no infection. 



3. PucciNiA on Carex Bonplandii minor Vasey, collected at 

 Granby, Colo., by Mr. E. Bethel, was sown on Aster Tzveedii, A. 

 paniculatus, A. multiflorus and A. Drummondii, with no infec- 

 tion. The determination of the host was made by Mr. Theo. 

 Holm. 



4. PucciNiA on Carex Backii Boott, collected in Colorado, by 



