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1902] 



THE UREDINEAi IN AMERICA 



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9 



rusts, both on Spartina and Fraxinus. Bessey^ records that in 

 1885 it infested the green ash trees about Lincoln, Neb,, to such 

 a degree as to attract the attention of casual passers. 



The teleutosporic form is equally common with the aecidial, 

 and is well represented in herbaria, where it has passed under the 

 name of Pi/c. Phragmitis for the most part. It was not until the 

 publication of the result of cultures by the writer 7 about two 



* 



years ago, that the autonomy of the species was recognized. 



f 



s 



h 



Fig. 2. — P, Fraxinata: fy three aecidiospores on Fraxinus lane eolata; gy six 

 uredospores, and [h) six teleutospores, both on Spartina cynosiiroides. 



The uredo form is very rarely collected, and the writer has 

 had much difficulty to secure material for study. The sori are 

 rather conspicuous when they first appear, but are usually not 

 abundant, and are soon replaced by the teleutospores. 



The aecidiospores and uredospores show a very remarkable 



similarity in color, form, and 



{fig' ^^ f 



Both 



have colorless walls, greatly thickened at the apex, and evenly 

 tuberculate. The contents are of the same shade of orange, a 

 color that speedily disappears with the death of the protoplasm. 

 In fact the uredospores differ in appearance from the aecidio- 

 spores chiefly in being a little more robust. The shape and 

 dimensions in the diagnosis above are for the spores when seen 



® Amer. Nat. ig : 886 ; see also ibid. 20 : S06. 7 Box. Gaz. 29 : 275- 



