72 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



1. Andropogon scoparius Michx. Little bluestem. 

 Dry open hillsides and open woods; common. Eastern U. S. (Schizachyrium 



scoparium Nash.) 



Like the other species of the genus an autumn grass. Sometimes called hroom 

 sedge, but this name more properly belongs to A. virginicus, although the specific 

 name refers to a broom. The seeds of this and all our other species except A.furcatus 

 are dispersed by the wind, the rachis disarticulating, the woolly joints with spikelets 

 attached being easily blown about. 



2. Andropogon furcatus Muhl. Big bluestem. 

 Open grassy ground and rocks along the Potomac ; frequent, Eastern U. S. 

 Taller than any other of our species of this genus. Often glaucous. A good forage 



grass. 



3. Andropogon elliottii Chapm. 



Sterile open ground; frequent; especially abundant in the open land at College 

 Park and near Chevy Chase. Southeastern U. S., especially on the Coastal Plain, 

 north to Del . 



Culms stiffer and not so tall as those of A. virginicus, the crowded inflated upper 

 sheaths bright pinkish or orange brown and persisting through the winter. 



4. Andropogon virginicus L. Broom sedge. 

 Dry sterile open ground, open woods, and old fields; common. Southeastern V. S. ? 



north to Mass. 



Especially characteristic of acid soils in old fields. Turning bright rosy or orange 

 brown in November and standing until late February, forming, together with Andro- 

 pogon elliottii. a conspicuous feature of the winter landscape. 



Andropogon trrnarius Michx. (A. argentcus Ell.) is listed in Ward'B Flora, but 

 probably does not occur within our limits. 



5. Andropogon glomeratus (Walt.) B. S. P. 



Open swamps; infrequent; Brightwood and eastward. Coastal Plain, from N. Eng- 

 southward. (A. macrour us Michx.) 



5. SORGHASTRUM Nash. 



1. Sorghastrum nutans (L.) Nash. Indian grass. 



Common in open dry ground, old fields, and open woods. Aug.-Sept. Eastern 

 U. S. (Sorghum nutans A. Cray; Sorghastrum avenaceum Nash.) 



The long panicles of golden brown spikelets with orange anthers are strikingly 

 handsome when in bloom, turning bronze at maturity. 



6. HOLCTJS L. Sorghum. 



To this genus belongs the cultivated //. sorghum L. (Sorghum rulgare Pers. ; Andro- 

 pogon sorghum Brot.), the varieties of which are known as sorghum or sorgo, Kafir, 

 Milo, Durra. and others, found occasionally growing spontaneously where the seed has 

 been accidentally scattered, 



1. Holcus halepensis L. Johnson grass. 



Commonly escaped from cultivation from Va. southward and westward throughout 

 the country; rare in waste ground in our region. Native of Eur. and Asia. (Sorghum 

 halepcnse Pers.) 



7, SYNTHERISMA Walt. 



Culms erect, branching at the base; rachis not winged 1. S. filiformis. 



Culms decumbent, sometimes extensively creeping, branching throughout; rachis 

 wing-margined. 



Foliage glabrous; fruit brown; first glume wanting 2. S. ischaemum. 



Foliage pilose; fruit pale gray; first glume minute 3. S. sanguinalis. 



