20 THE AMERICAN MIDLAND NATURALIST 



to Prof. Hitchcock and Dr. George T. Moore of the Missouri 

 Botanical Garden, I am under obligations for numerous citations 

 furnished and for verifications of publications; to all of the above 

 I herein return thanks for the many courtesies extended. 



For the Missouri species now included, or were formerly included, 

 in the genus MuhlEnbergia, I offer the following: 



Key to the Missouri Muhlenbergias. 



Panicles contracted, narrow, often numerous, often slender, 

 the branches short, erect or appressed; ligules usually short or 

 minute. i. MuhlEnbergia. 



Panicles open, single, terminal, very large, their branches long 

 and spreading, slender, the pedicels hair-like, drooping; ligules 

 elongated; lemmas with long awns. 2. Podosemum. 



I. MuhlEnbergia Schreber; Gmelin, Syst. Nat. 2:171. 1791. 



A genus of about 30 species, mostly American, a few Asiatic, 

 divisible into several rather well-marked groups, the type-species 

 MuhlEnbergia Schreberi Gmelin. As here treated, the species 

 naturally fall into four groups or sections as follows: 



Glumes wanting, minute or very short, or in one species a little 

 longer, blunt or obtuse or in one species acuminate; plants decum- 

 bent at the base, from weak or slender rootstocks; lemmas usually 

 long-awned or in one species rather short-awned. 



A. MuhlEnbergia proper. 



Glumes broad, ovate, acute, much shorter than the lemmas; 

 lemmas acute or awned; rootstocks stout, scaly. 



B. Stenocladium section. ■ 



Glumes narrow, acuminate or aristate, nearly as long as or 

 exceeding the lemmas in length; rootstocks stout, scaly. 



C. AcROxis section. 

 Glumes broad, cuspidate; panicle very much contracted, narrow; 

 plants without rootstocks. 



D. EucLADiUM section. 



A. MuhlEnbergia proper. 



Glumes less than one-fourth the length of the spikelets, minute 

 or wanting, blunt or obtuse; lemmas with awns 3-5mm. long; 

 rootstocks rather weak. i. MuhlEnbergia vSchreberi. 



