ANDROPOGONE& 



171 



Brot. for the first and Sorghum 

 vulgare Pers. or Andropogon 

 Sorghum (L.) Brot. for the 

 second. 



H.halepensislj. Johnson-grass. 

 Culms usually 3 to 5 feet tall, 

 erect, smooth, often glaucous, pro- 

 ducing strong creeping rhizomes; 

 sheaths smooth; ligule membra- 

 naceous, about 2 mm. long, the 

 upper half a ciliate fringe; blades 

 smooth or nearly so, somewhat 

 scabrous on the margins, 1 to 3 feet 

 long, mostly ^ to ^ inch wide, 

 tapering to a fine point, the white 

 midrib conspicuous; panicle open 

 and spreading, 6 inches to 2 feet 

 long, usually more or less reddish 

 or purple, the branches 2 to 4 

 together, naked below, pubescent 

 at the base; spikelets somewhat 

 crowded along the upper part of 

 the branches, in pairs or the termi- 

 nal in 3's, 1 sessile and fertile and 

 1 or 2 pediceled and staminate; 

 fertile spikelet about 5 mm. long, 

 flattened dorsally, elliptical or ovate- 

 lanceolate, indistinctly nerved, firm 

 and coriaceous, at first pubes- 

 cent but later becoming smooth 



FIG. 17. Holcus halepensis. Inflorescence 

 and rhizomes, X M. a terminal fertile spike- 

 let with two staminate spikelets, X3. 



