176 



POACEAE 



44. CHLORIS Swartz, Prod. Veg". Ind. Occ. 25. 1788. 



Spikelets 1-flowered, sessile in 2 rows along one side of a continuous rachis, the rachilla 

 disarticulating above the glumes, produced beyond the perfect floret and bearing 1 to 

 several reduced florets consisting of empty lemmas, these often truncate and, if more than 

 one, the smaller ones enclosed in the lower, forming a usually club-shaped rudiment ; 

 glumes somewhat unequal, the first shorter, narrow, acute; lemma compressed, usually 

 broad, 1-5 nerved, often villous on the callus, and villous or long-ciliate on the keel or 

 marginal nerves, awned from between the short teeth of a bifid apex, the sterile lemmas 

 awned or awnless. Perennial or sometimes annual tufted grasses with flat blades and 2 

 to several often showy and feathery spikes aggregate at or near the summit of the culms. 

 [Named for Chloris, the goddess of flowers.] 



Species about 60 in tlie warmer countries of the world. Type species, Agrostis cniciafa L. 



1. Chloris virgata Swartz. 

 Silky Chloris. Fig. 399. 



Chloris virgata Swartz, Fl. Ind. Occ. 1: 203. 1797. 



Chloris elcqaus H. B. K. Nov. Gen. & Sp. 1: 166. pi. 49. 

 1816. 



Annual ; culms erect or spreading, 30-100 cm. 

 tall, smooth ; sheaths smooth, much compressed, 

 especially the basal, the uppermost often inflated 

 around the base of the inflorescence; spikes 

 several, feathery, suberect, 6-12, pale or dark- 

 colored, 2-7 cm. long; spikelets imbricated; 

 glumes 1-nerved, the second about 3 mm. long, 

 awn-pointed ; lemma somewhat fusiform, about 

 2 mm. long, 3-nerved, short-pilose at base and 

 along the lower half of the keel, long-pilose on 

 the margins near the apex, with a slender straight 

 awn 'about 10 mm. long from just below the apex; 

 rudiment reaching about to the tip of the fertile 

 floret, truncate, the awn somewhat shorter. 



Fields and waste places, Colorado Desert to Texas 

 and tropical America. Dec. -Feb. Type locality: Island 

 of Antigua. 



Chloris verticillata Nutt. Perennial; culms 15-35 cm. tall; sheaths compressed; blades 2.5-8 cm. long, 

 2-4 mm. wide; sjiikes slender, stiff, divergent, 5-10 cm. long, in 1 or 2 whorl; spikelets 3 mm. long, the 

 awns of the lemmas about 5 mm. long. 



Open dry ground, Missouri to Colorado and Texas; introduced in California (Berkeley). Type locality: 

 Arkansas. 



Chloris radiata ("L.) Swartz, with paler, more slender racemes than in C. virgata, has been collected on 

 ballast at Linnton, Oregon (Nelson). 



45. BOUTELOUA Lag. Var. Cienc. 2': 13-k 1805. 



Spikelets 1-flowered, with the rudiments of 1 or more florets above, sessile in 2 rows 

 along one side of the rachis; glumes unequal, 1-nerved, acuminate or short-awned, the 

 first shorter and narrower; lemma as long as the second glume or a little longer, 3-nerved, 

 the nerves extending into short or usually rather long awns; the internerves usually ex- 

 tending into teeth ; palea 2-nerved, sometimes 2-awned ; rudiment various, usually 3-awned, 

 a second rudimentary floret sometimes present. Perennial or sometimes annual, low or 

 moderately tall grasses with 2 to several or many spikes, or soinetimes solitary, along a 

 main axis, the spikelets 2 to many in each spike, pectinate or more loosely arranged and 

 appressed, the rachis of the spike usually produced beyond the insertion of the spikelets 

 as a bristle or point. [Named for the brothers Boutelou, Spanish gardeners.] 



Species 38, all American and chiefly North American. Type species, Bouteloua racemosa Lag. 



Spikes containing 1-3 spikelets, numerous along a main axis. 

 Plants perennial. 

 Plants annual. 



1. B. cjirtifyendula. 



2. B. aristidoides. 



Spikes usually few, containing numerous spikelets. 

 Plants annual. 



Awns about 3 mm. long; spikes 2-4. 



Awns barely protruding; spikes 4-6 or more. 



Plants perennial. 

 Spikes several. 



Spikes narrow, strictly 1 -sided; spikelets numerous. 

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

 Spikes usually 1-3. 



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



Rachis produced beyond the spikelets as a naked ooint; glumes oromiiiently papillose-hispid 



• .S. B. hirsuta. 



3. B. arenosa. 



4. B. barbata. 



5. B. rothrockii. 



6. B. radicosa. 



