1889-] BOTANICAL GAZETTE. 285 



Study of Montana Erysiphesr. 



F. D. KELSEY. 



In the author's experience, a wide difference exists in 

 Montana as to the relative quantity of the Erysifihcte and the 

 Urcdiucce, the latter being by far the more numerous and on 

 a wider range of hosts; but the Erysiphcce, where they do 

 occur, are beautiful in form, abundant on the hosts, and 

 marked in perfection of development. 



Erysiphe Linkii Lev. Found on our prominent and 

 abundant Artemisia Ludoviciana Nutt. I obtained these 

 plants in Helena, Montana, September 17, 1888, and also in 

 September, 1889. A careless observer would not see the 

 fungus at all, or mistake it for particles of dust. It is evi- 

 dent enough in herbarium specimens, but the whole appear- 

 ance of the host is such as to make it hard to see the tungus 

 on the living plant. The identification of this species wa 

 made by Mr. E. W. D. Holwav, of Deconih, Iowa, to whom 

 the author owes a debt of gratitude for kindness and atten- 

 tion. 



Erysiphe communis (Wallr.) Fr. (1) On Aster commu- 

 tatus Gray, September, 1888, at Helena. This host has been 

 doubted by one eminent botanist and reaffirmed by another. 

 If it be not A. commutatus it comes far too near to be sepa- 

 rated into even a good variety, unless botanists are willing 

 to multiplv species. Whether the fungus be abundant can 

 not now be told. Only once have I collected it on this host, 

 and then obtained but a few inferior specimens. (2) On 

 Ranunculus Cymbalaria Pursh. This host is an abundant 

 one in Montana, and is most richly covered with the tungu 

 in September and October. The host grows only a tew 

 inches in height, and always in damp places, thns inviting 

 most genially the visits of the fungus. (3) On Geramum 

 Richardsani Fisch. & Mev. This specimen was collected at 

 Sand Coulee bv my friend, Mr. F. W. Anderson. The per- 



ithecia are very few, an unusual and possibly accidental 

 matter. (4) On Gutierrezia Euthamu* Torr. & Gray. 1 hi 

 pecimen was also found by Mr. Anderson, and its date is 

 remarkably early, July 27. i'888. The host is but slight; y 

 affected, and no eye but -that of a skilled observer would 

 ever have seen the fungus, yet it is on both stem and 

 leaves. (5) On Lufinus farviflorus Nutt. Pentheca abun- 



