The American Midland Naturalist 



PUBLISHED BI-MONTHLY BY THE UNIVERSITY 

 OF NOTRE DAME, NOTRE DAME, INDIANA 



VOL. VI. MARCH, 1919. NO. 



The Missouri Muhlenbergias. 



BY BENJAMIN FRANKLIN BUSH. 



Any one in recent years attempting to name specn 

 MuHLENBERGiA by the books, must have been struck by the wide 

 difference of opinion in the presentation of the species in the 

 Robinson and Fernald Gray's New Manual, and the Britton and 

 Brown Illustrated Flora. This difference of opinion in treating 

 the species of this genus in some cases is so marked as to cause one 

 to wonder if there is not something wrong with our understanding 

 of the species. This difiference of opinion is most marked with the 

 members of the Mexicana group, a most perplexing and critical 

 one, the species of which present so many variations in calms, 

 leaves and floral characters. 



It was formerly thought that the species of this, and those of the 

 Acroxis group, were either awned or awnless, this belief causing 

 much confusion in the treatment of the species and the naming of 

 specimens: but it began to be suspected that those species which 

 were habitually awnless sometimes presented awned forms, and 

 those species that were ordinarily awned, sometimes presented 

 awnless forms. This suspicion was first voiced by vScribner,' who 

 announced that M. Mexicana and M. sobolifera often or 

 occasionally presented awned forms, and he went so far as to 

 describe awned forms of these species, ^ and noted that M. TENui- 

 fIvORA and M. Torreyi were occasionally awnless. 



My conclusions after a careful examination of several hundred 

 sheets of specimens, are, that Scribner was correct in the main, but 

 that what he took to be awned forms or varieties of M. Mexicana 

 and M. sobolifera are really good distinct species, which I herein 

 propose as new. 



' Scribner, Rhodora 9:18. 1907. ^ Scribner, Rhodora 9:18. 1907. 



