MANUAL OF THE GRASSES OF THE UNITED STATES 779 



158. CHRYSOPOGON Trin. 1181.) Annual; culms 60 to 120 cm. 



(Rhavhis Lour. ) ^ a ^j erect or somewhat decumbent 



~ ., , . . ;1 ., t at base: blades flat, mostly 4 to 8 



Spikelets m threes, one sessile and mm wid ide loQS the axis 5 



perfect, the other two pedicellate and to 10 cm j the branches few 



sterile, or sometimes a pair below, ve glend 5 to g cm { gesgile 

 one fertile and one sterile; fertile ikelet about L5 cm } inc l u ding 



spikelet terete, the glumes coriaceous ; the glender villoug callug about ? mm 



sterile and fertile lemmas thin and { thig disarticu i ating by a long . 



hyaline, the latter awned. Perennial obH u the ti Q | the dicel 



grasses, or, our species annual with thug viUoug on one gid awn gtout 



open panicles, the three spikelets b geniculate, twisted below, 



(reduced raceme) borne at the ends about 15 cm j _ Sandy 



of long, slender naked branches. ine wood nd and field 



Type species , Andropogon gryllus L. Florida; Cuba . The fertile sp i ke i e t s 



Name from Greek chrysos, golden, regemble the fruits of certain gpecies 



Vogon beard. of su guch ag ^ spartea L . 



1. Cnrysopogon pauciflorus ^ r 



(Chapm.) Benth. ex Vasey. (Fig. 



159. HETEROPOGON Pers. 



Spikelets in pairs, one sessile, the other pedicellate, both of the lower few 

 to several pairs staminate or neuter, the remainder of the sessile spikelets 

 perfect, terete, long-awned, the pedicellate spikelets, like the lower, staminate, 

 hat, conspicuous, awnless; glumes of the fertile spikelet equal, coriaceous, the 

 first brown-hirsute, infolding the second; lemmas thin and hyaline, the fertile 

 one narrow, extending into a strong bent and twisted brown awn; palea 

 wanting; glumes of the staminate spikelet membranaceous, the first green, 

 faintly many-nerved, asymmetric, one submarginal keel rather broadly 

 winged, the other wingless, the margins inflexed, the second glume narrower, 

 symmetric ; lemmas hyaline ; palea wanting. Annual or perennial, often robust 

 grasses, with flat blades and usually solitary terminal racemes; rachis slender, 

 the lower part, bearing the pairs of staminate spikelets, continuous, the 

 remainder disarticulating obliquely at the base of each joint, the joint forming 

 a sharp-barbed callus below the fertile spikelet, the pedicellate spikelet readily 

 falling, its pedicel remaining obscured in the hairs of the callus. Type species, 

 Heteropogon glaber Pers. (H. contortus). Name from Greek heteros, different, 

 and pogon, beard, alluding to the difference between the awnless-staminate and 

 awned-pistillate spikelets. 



One species, H. contortus, has a world-wide distribution. It is a good forage 

 grass in the Southwest; if grazed constantly the troublesome awns do not 

 develop. In the Hawaiian Islands, where it is called pili, it is an important 

 range grass on the drier areas; also used there by the natives to thatch their 

 grass huts. The mature fruits are injurious to sheep. 



Plants perennial, less than 1 m. tall; first glume of staminate spikelet usually papillose- 

 hispid..... 1. H. CONTORTUS. 



Plants annual, usually more than 1 m. tall; first glume of staminate spikelet with a row of 

 glands along the back, glabrous 2. H. melanocarpus. 



1, Heteropogon contortus (L.) 



Beauv. ex Roem. and Schult. Tangle- sheaths smooth, compressed-keeled ; 



head. (Fig. 1182.) Plants perennial, blades flat or folded, 3 to 7 mm. 



tufted; culms 20 to 80 cm. tall, wide; raceme 4 to 7 cm. long, 1-sided; 



branched above, the branches erect; sessile spikelets about 7 mm. long, 



