136 GEAMINEAE 



Rachilla prolonged beyond the perfect floret and bearing a sterile (rarely stam- 

 inate) floret, a second or third rudiment often present. Lemma broader, 3 to 

 5-nerved, 2 to 4-toothed or cleft, usually awned between the teeth. Palea about 

 as long as the lemma, bidentate, the 2 keels scabrous. Sterile floret sometimes 

 reduced to awns, rarely obsolete. Annuals or usually perennials with narrow 

 blades and few or numerous short spikes scattered along a common axis. — 

 Species about 30, all American, mostly of the Mexican plateau. (Tbe brothers 

 Claudio and Esteban Boutelou, Spanish gardeners.) 



Spikes coutaining 1 to 3 spikelcts, numerous along a main axis. 



Plants perennial 1. B. curtipendula. 



Plants annual ' 2. B. aristidoides. 



Spikes usually few, containing numerous spikclets. 

 Plants annual. 



Awns about ll-. lines long; spikes 2 to 4 3. B. arenosa. 



Awns barely protruding ; spikes 4 to 6 or more 4. B. barbata. 



Plants perennial. 

 Spikes several. 



Spikes narrow, strictly l-sided; spikelets numerous 5. B. rothrocMi. 



Spikes broad, loose, irregularly 1-sided; spikelets few 6. B. radieosa. 



Spikes usually 1 to 3. 



Eacliis not prominently produced; glumes sparsely hairy 7. B. gracilis. 



Rachis produced beyond the spikelets as a naked point; glumes prominently papillose- 

 hispid 8. B. hirsuta. 



1. B. curtipendula Torr. Perennial: culms erect, 1 to 4 feet high; spikes 

 numerous on an elongated rachis, y^ to '}4 ^U'"'' long, reflexed, mostly turned to 

 one side ; glumes narrow, acuminate, scabrous on keel and somewhat so on the 

 back, the second about 21/2 lines long; lemma as long as second glume, ovate- 

 lanceolate, 3-uerved, scabrous toward tip, 3-toothed, the palea about as long; 

 rudiment as long as lemma, 4-lobed, 3-awned between the lobes, the lateral 

 lobes and awns shorter. 



Plains and rocky hills, Montana and Ontario, south to Mexico. 

 Loc. — Santa Eosa Mt., San Jacinto Eange, Hall 2138. 



Eefs. — BouTELOUA CURTIPENDULA Torr. in Emory, Mil. Eeconn. 154. 1848. Chloris cur- 

 tipendula Michx. Fl. Bor. Am. 1: 59. 1803. Boutelova raremosa Lag. Var. Cienc. 2*: 141. 1805. 



2. B. aristidoides Griseb. Annual ; cidms spreading, slender, 6 to 15 inches 

 high ; sjiikes several, slender, about 1/2 inch long, the 1 to 3 spikelets distant, 

 appressed to the rachis, the latter ending in a slender naked point; glumes 

 narrow, acuminate, the first I/2 as long as the second ; lemma narrowly lanceo- 

 late, 3-nerved, the nerves pilose, the lateral ending in awned teeth as long as 

 the central acuminate point; rudiment consisting of a pilose pedicel and 3 

 awns longer than the spikelet. 



Open ground, deserts and foothills, southern California to western Texas and 

 south into South America. San Diego, Orcutl in 1890; Colorado Desert, Bran- 

 degee in 1905; Colorado River, Riverside Co., Hall 5962. 



Eefs. — BoOTELOUA ARISTIDOIDES Griseb. Fl. Brit. W. Ind. 537. 1864; Thurb. in Wats. Bot. 

 Cal. 2: 291. 1880. Diiiebra aristidoides H.B.K. Nov. Gen. & Sp. 1 : 171. 1816. 



3. B. arenosa Vasey. Annual ; culms spreading or prostrate, about 6 inches 

 long ; spikes 2 to 4, many-flowered, about 1/0 inch long ; glumes 1-nerved, the 

 first 1 line, the second II/2 lines long; lemma a little shorter than the second 

 glume, pilose below, 4-lobed, the lateral lobes short, 3-awned from between the 

 lobes, the awns about ly^ lines long; palea 4-toothed, 2-awned ; rudiment 1/2 

 line long, triangular-truncate, pilose at base, 4-lobed, with 3 long awns between 

 the lobes. 



