352 American Midland Naturalist Monograph No. 7 



4. Spikelets 3 mm long. 



5. Bristles 1-3; panicle thick, lobed or interrupted, purplish 

 or yellowish; cult, and sometimes spontaneous; introd. 

 from Eurasia. July-Sept. Italian Millet or Hun- 

 garian Grass S. italica (L.) Beauv. 



5. Bristles 5-15 at the base of each spikelet; panicles 

 straight, about 1 cm thick, 5-10 cm long; a common 

 weed in waste ground and along roads; nat. from 

 Eur. June-Sept. Yellow Foxtail [S. glauca sensu 



auth., non (L.) Beauv.] 



S. lutescens (Weigel) F.T.Hubb. 



73. Cenchrus L. — Sandbur 



C. pauciflorus Benth. Sandy soil, cult, ground, or roadsides. July- 

 Sept. [C. loyigispinus (Hack.) Fern.] 



Tribe 10. Andropogoneae — Sorghum Tribe 



74. Andropogon L. 



1. Racemes usually borne singly on the few to many branches, 3-6 

 cm long; joints of the rachis clavate; sandy or prairie soil 



and open woods. Aug. -Oct. Little Bluestem 



...A. scoparius Michx. 



1. Racemes in fascicles of 2-7. the common peduncle enclosed in 

 a bract-like sheath or spathe; joints of the rachis not clavate. 



2. Pedicellate spikelet staminate, as large as the sessile spikelet; 

 racemes 5-13 cm long, exserted on a naked peduncle, the 

 uppermost sheath inconspicuous, not inflated; rachis straight, 

 the hairs inconspicuous and shorter than the spikelets; 

 stamens 3; prairie soil. July-Sept. Big Bluestem [A. ge- 



rardi Vitm. (?)] A. jurcatus Muhl. 



2. Pedicellate spikelet reduced to 1 or 2 empty glumes or a mere 

 pedicel; racemes 1.5-4 cm long; stamen 1. 

 3. Upper sheaths inflated, spathe-like; awns coiled at the base; 

 sessile spikelets 4-4.5 mm long; open woods, s. 111., rare 

 ...A. liliottii Chapm. 



3. Upper sheaths not inflated; awns straight or somewhat 

 curved; sessile spikelets 3-3.5 mm long; fields and road- 

 sides in the s. half of the state. Sept.-Oct. Broom-sedge 

 A. virginicus L. 



75. Miscanthus Anderss. 



M. saccharifiorus (Maxim.) Hack. Cultivated for ornament, rarely 

 persisting; introd. from Asia; Du Page and Rock Island counties. 



