GENERA OF GRASSES OF THE UNITED STATK-. 273 



much shorter than the very thin sterile and fertile lemmas. The 

 awn is about 6 inches long, twisted and bent. The species before 

 maturity furnishes forage on the grassy pinelands of southern 

 Florida. 



136. HETEBOPOGON 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 spikelots, 

 like the lower, staminate, flat, conspicuous, awnless; glumes of the 

 fertile spikelet equal, coriaceous, the first brown-hirsute, infolding 

 the second ; lemmas thin and hyaline, the fertile one narrow, extend- 

 ing into a strong bent and twisted brown awn ; palea wanting; glumes 

 of the staminate spikelet membranaceous, the first green, faintly many 

 nerved, asymmetric, one subrnarginal 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 soli- 

 tary racemes terminal on the culms and branches ; 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 pedicel- 

 late spikelet readily falling, its pedicel remaining, obscured in the 

 hairs of the callus. Species about seven, in the warmer regions of 

 both hemispheres; two in the United States, from Florida to Arizona. 



Typo spocios : Ifftnrop'jf/rm yJnl<"r Pers. 



Heteropogon Pers., Syn. PI. 2 : 533. 1807. Persoon describes two species, H. 

 ylaber, of which he gives as synonyms Andropoyon allioni DC. and A. cf/n- 

 tortus All., and H. hirtun, of which ho gives as a synonym Andropoyon con- 

 tortiiH L. The first ;li<- type. 



Spirotheros Raf., Bull. Hot. Serins 1 : 221. 1830. A single species, " Stipa 

 melanocarpa, Muhl., Andropoyon nwianwaritus Ell.," is given. 



The two species in the United States are Heteropogon contortus 

 (L.) Beauv. (fig. 105), a perennial, 1 to 3 feet tall, the first glume 

 of the staminate spikelets papillose-pilose, sometimes sparsely so, 

 anrl 77. melo/nacoppus (Ell.) Benth., an annual, 4 to 7 feet tall and 

 often much branched, the first glume of the staminate spikelets bear- 

 ing a row of glands along the back. The first species is found in 

 rocky places from Texas to Arizona. The second is found in Florida, 

 Georgia, and Alabama; also in Arizona. The oil glands on the in- 

 florescence of the latter give the plant an odor like that of citronella 

 oil. 



Heteropogon contortus is an important forage grass but does not 

 extend far into the United States. In the Hawaiian Islands, where 

 it is called pili, it is an important range grass on the drier areas. It 

 was used by the natives to thatch their grass huts. The mature fruits 

 are injurious to sheep. 



97769 19 Bull. 772 - 18 



