AMERICAN UREDINEvE. 317 



National Herbarium a scanty specimen of the same rust on 

 an undetermined species of Muhlenbergia, but which Prof. F. 

 L. Scribner has kindly examined for us and considers to be 

 M. exilis, collected by E. Palmer in Mexico in 1886, and also 

 an ample specimen on Muhlenbergia tenella collected by C. 

 G. Pringle in Mexico in 1890. 



This species does not appear to have been collected north 

 of Mexico. The name has often been applied, however, to 

 the species following, which it somewhat resembles. 



50. PUCCINIA MUHLENBERGIA sfl. 710V. 



50a. On Muhlenbergia diffusa Willd., II. iii, Lafayette, Ind., Miss 

 Snyder. 



50b. On Muhlenbergia mexicana (L.) Trin., Ill, Decorah, Iowa, Hol- 

 way. 



$qc. On Muhlenbergia mexicana (L. ) Trin., Ill, Rockport, Kans., 

 Bartholomew. 



5od. On Muhlenbergia racemosa (Michx.) B. S. P. (M. glomerata 

 Trin.), Ill, O'Neill, Neb., Bates. 



$oe. On Muhlenbergia racemosa (Michx.) B. S. P., Ill, Phillips Co., 

 Kans., Bartholomew. 



SYN: 



1885. Puccinia zvindsorixe Burrill non Schw., Bull. 111. 

 Lab. Nat. Hist. 2: 197. 



O. I. Spermogonia and secidia unknown. 



II. III. Sori hypophyllous or sparingly amphigenous, 

 prominent, oblong or linear-oblong, soon naked, ruptured 

 epidermis inconspicuous. II. Uredosori light brown, pul- 

 verulent; uredospores globose or globose-elliptical, 22-30/A in 

 diameter, wall thin, yellowish brown, closely and distinctly 

 echinulate, pores about 5, scattered. III. Teleutosori choco- 

 late-brown; teleutospores obovate or oblong-obovate, dark 

 brown, 19-27 by 30-40//., not constricted at the septum, nar- 

 rowed somewhat toward the base, side walls rather thin, apex- 

 rounded and somewhat thickened, pedicel hyaline, tinted, 

 stout, firm, about the length of the spore. 

 V— 3 16 



