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Mycologia 



present time to say what the aecial hosts of the other race or races 

 may be, but they are likely to be some other species of the Ber- 

 beridaceae or some closely allied family. Puccinia apocrypta pre- 

 sents a somewhat similar situation. As this rust, however, has 

 been cultured only by sowing aeciospores from Hydro phyllum on 

 grass hosts, no cultures having been successfully made by sowing 

 teliospores upon a series of Hydrophyllaceous and Boraginaceous 

 species, the aecial host range for this species can not be given with 

 certainty. It is probable, however, that besides Hydrophyllum 

 capitatum, which has been shown by culture to be an aecial host, 

 other species of Hydrophyllum and species of Phacelia and Nyc- 

 tclca will be found to belong here, possibly connected with different 

 races. Whether the Boraginaceous aecia of this country also be- 

 long here can only be settled definitely by cultures. > It seems prob- 

 able, however, that a part of these aecia will be found to be con- 

 nected with rusts identical with or very similar to Puccinia bromina 

 and Puccinia sccalina, and presumably will be found to have their 

 connections with Bromus and Agropyron rusts. Puccinia Koe- 

 Icriac offers but little information as to its host range, as its aecial 

 connection is founded on only one culture to Mahonia Aquifolium, 

 and it is likely that other Berberidaceous- species will be found to 

 serve as hosts. A thorough understanding of these species can be 

 reached only through the gradual accumulation of field evidence of 

 associations such as those obtained by Mr. Bethel and Dr. Coons 

 • and by cultures to determine both grass and aecial hosts of such 

 rusts. The presence or absence of races and their limitations 

 within the species and the limitations and relations of the species 

 to each other can be determined only by such methods. 



To Prof. H. S. Jackson the writer is indebted for helpful sug- 

 gestions from his knowledge of western rusts. Dr. J. C. Arthur 

 especially has given many helpful suggestions, drawn from his 

 large acquaintanceship and work with this group. The writer also 

 is indebted to Mr. E. Bethel and Dr. G. H. Coons for their dis- 

 criminating field observations and for material. 

 Department of Botany, 



Agricultural Experiment Station, 

 Lafayette, Indiana. 



