GRAMINEAE (GRASS FAMILY^ 144 



52. GYMNOPOGON Beauv 



Spikelets with 1 perfect flower, sometimes 1 or 2 neuter or staminate subses- 

 sile florets above tlie perfect one, remote along one side of a filiform continuou* 

 rhachis, forming slender unilateral spikes; rhachilla prolonged beyond tiie floret 

 as a slender often awned rudiment ; glumes narrow, subequal, Agid, scabrous on 

 the strong keel, equaling or exceeding the florets ; lemma thin, bearing a slender 

 straight awn from just below the apex ; palea about as long 

 as the lemma. — Perennials, with short rather broad rigid 

 leaves and numerous slender spikes, at first erect, at length 

 widely divaricate or reflexed. (Name composed of yu/xv6s^ 

 naked, and irdr^wv, a begird, alluding to the reduction of the 

 abortive flower to a bare awn.) 



1. G. ambiguus (Mlchx.) BSP. Culms tufted from a short 

 rootstock, rigid, erect or ascending, 2-5 dm. high ; sheaths 

 overlapping, blades often approximate, thick, rigid, spreading, 

 4-6 cm. long, 1 cm. or more wide ; spikes solitary or in 2's 

 along a striate axis, becoming widely divaricate when exserttd 

 from the sheath, spikelet-bearing to the base; awn of floret 

 longer than the glabrous lemma; rudiment long-awned. ^gg ^ ambieuas 

 (G. racemosus Beauv.) — Sterile sandy or gravelly ground, i^ft''^.,^i/' 

 N. J. to Mo., Fla., and Tex. Aug., Sept. Fig. 135. Spikelet x2i4 



2. G. brevifblius Trin. Resembling the preceding ; culms 



more slender, from a decumbent base; leaves 2-4 dm. long, 4-9 mm. wide, 

 involute in drying ; spikes usually less numerous, more distant, naked at the 

 base, spikelet-bearing from about the middle ; awn shorter than the hairy lemma; 

 one or two .sterile florets sometimes present, rudiment usually awnless. — Sandy 

 ground, N. J., and south w. 



53. CHL6RIS Sw. 



Spikelets with 1 perfect floret, sessile in 2 rows along one side of a continuous 

 rhachis, forming unilateral spikes ; rhachilla prolonged behind the palea and bear- 

 ing 1 or more rudimentary awned sterile lemmas ; glumes unequal, narrow, 

 acute, keeled ; lemma often ciliate on the back or margins, 

 1-o-nerved, the mid-nerve nearly always prolonged into a 

 slender awn; palea about equaling the lemma; grain free 

 within the lemma and palea. — Usually perennial grasses with 

 flat leaves and digitate spikes. (Named for Chloris, the god- 

 dess of flowers.) 



1. C. verticillata Nutt. Culms 1-4 dm. high, erect, or de- 



-, cumbent and rooting at the nodes ; sheaths compressed ; leaves 



"^ ^ -tTV^Q^^ obtuse, light green; spikes several in 1-3 whorls, slender, 



spikeiet x2. g^jQ ^^ j^^g. spikelets 3 ram. long, with awns about 5 mm. 



long; sterile lemma one. — Prairies, e. Kan. and southwestw. June. — At 



maturity the inflorescence breaks away and forms a tumbleweed. Fig. 136. 



54. BOUTELOtTA Lag. Mesquite Grass 



Spikelets 1-2-flowered, crowded and sessile in 2 rows along one side of a con- 

 tinuous flattened rhachis, which usually projects beyond the spikelets ; rhachilla 

 prolonged beyond the perfect floret and bearing a sterile (rarely staminate) 

 floret, a ser!ond or third rudiment often present ; glumes unequal, keeled ; lemma 

 broader, 3-6-nerved, 3-5-toothed or cleft, 3 of the divisions usually awn-pointed ; 

 palea about the length of the lemma, bidentate, the 2 keels scabrous ; sterile 

 floret sometimes reduced to the awns, rarely obsolete. — Our species perennial, 

 with narrow flat or convolute leaves, and unilateral spikes nearly sessile along 

 a common axis. (Named for Claudio Boutelou, a Spanish writer upon flori- 

 culture and agriculture.) 



<SKAX'S MANUAL 10 



