April] BOTANICAL GAZETTE 2^ 



this spring near Lafayette, Ind., upon Ulmaria rubra (Spircea 

 lobata), in the bright red creoma stage. Feeling at first uncer- 

 tain of the identity of the rust, the caeoma spores were sown 

 upon the Ulmaria, and also upon Salix, Convolvulus, and Ipomoea, 

 with the result that it grew only upon Ulmaria, producing at first 

 uredospores and afterward teleutospores. An after-sowing of 

 uredospores upon Ulmaria gave a crop of more uredospores. The 

 dates are as follows : 



May 17, Caeomospores sown on Ulmaria rubra; May 30, uredo ; July 



teleutospores. 

 May 17, Caeomospores sown on Salix longifolia ; no infection. 

 May 23, Caeomospores sown on Convolvulus septum ; no infection. 

 May 24, Caeomospores sown on fpomosa pandurata ; no infection. 

 June 16, Uredospores sown on Ulmaria rubra ; July , uredospores. 



7. Puccinia Americana LagJi. 

 This grass rust on various species of Andropogon is very 

 common throughout North America, but has been generally con- 

 founded with Puccinia Andropogi Schw., which has the same range 

 and affects the same hosts. The teleutospores are barely distin- 

 guishable, but the uredospores are entirely unlike those of 

 P. Americana, being large and thin walled, those of P. Andropogi 

 small and thick walled. The detection of the aecidium is due 

 to the careful observation of Mr. William Stuart, who noticed 

 that plants of Pentstemon pubescens, growing near Andropogon 

 bearing teleutospores of the previous year, were well covered 

 with aecidia [sEcidium Pentstemonis Schw.), while the same spe- 

 cies in other localities was quite free. With this hint sowings 

 were undertaken. Teleutospores from Andropogon scoparius were 

 sown on Pentstemon pub esc etis and aecidia appeared in great abun- 

 dance and vigor; aecidiospores were sown on Andropogon and 

 large, thin-walled, brown uredospores appeared. The results 

 were ample and complete, and were further emphasized by 

 similar results subsequently obtained by Mr. Stuart. The dates 

 are as follows : 



May 3, Teleutospores from Andropogon scoparius sown on Pentstemon 

 pubescens ; May II, spermoi<onia ; May 20, aecidia. 



