MANUAL OF THE GRASSES OF THE UNITED STATES 715 



139. OL/YRA L. 



Plants monoecious; inflorescence paniculate; pistillate spikelets 

 borne on the ends of the branches of loose panicles, the smaller stami- 

 nate spikelets pedicellate below the pistillate ones, sometimes the upper 

 branches all pistillate and the lower ones all staminate; pistillate 

 spikelets rather large; first glume wanting; second glume and sterile 

 lemma herbaceous, often caudate-acuminate; fruit bony-indurate ; 

 staminate spikelets readily deciduous; glumes and sterile lemma want- 

 ing, the lemma and palea membranaceous. Mostly tall perennials 

 with broad flat blades, contracted into a petiole, and open or con- 

 tracted panicles of glabrous spikelets. Type species, Olyra latifolia. 

 Name from olura, an old Greek name for a kind of grain. 



1. Olyra latifolia L. (Fig. 1600.) Glabrous perennial, bamboolike 

 in aspect, commonly 5 m tall, with flat, firm, asymmetrically lanceo- 

 late-oblong, abruptly acuminate blades commonly 20 cm long and 

 5 cm wide, and ovoid panicles 10 to 15 cm long, the branches stiffly 

 ascending or spreading, each bearing a single large long-acuminate 

 pistillate spikelet at the thickened summit and several small slender- 

 pediceled staminate spikelets along the branches. % — Said to 

 occur in the region of Tampa Bay, Florida, but the record is doubtful; 

 tropical America; Africa. 



TRIBE 13. ANDROPOGONEAE 



140. IMPERATA Cyrillo 



Spikelets all alike, awnless, in pairs, unequally pedicellate on a 

 slender continuous rachis, surrounded by long silky hairs; glumes 

 about equal, membranaceous; sterile lemma, fertile lemma, and palea 

 thin and hyaline. Perennial, slender, erect grasses, from hard scaly 

 rhizomes, with terminal narrow silky panicles. Type species, 

 Imperata cylindrica. Named for Ferrante Imperato. 



Spikelets 4 mm long, the hairs at base twice as long; panicle oblong, rather 



lax 1. I. BRASILIENSIS. 



Spikelets 3 mm long, the hairs 3 times as long; panicle elongate 2. I. hookeri. 



1. Imperata brasiliensis Trin. (Fig. 1601.) Culms 50 to 100 cm 

 tall, from scaly rhizomes; leaves crowded below, 3 to 8 mm wide, the 

 lower blades elongate, those of the culm short, the uppermost much 

 reduced; panicle dense, pale or silvery, mostly about 10 cm long; 

 spikelets 4 mm long. % — Pinelands, prairies, and Everglades, 

 southern Florida; tropical America at low altitudes. 



2. Imperata hookeri Rupr. Satintail. (Fig. 1602.) Resembling 

 /. brasiliensis; culms 1 to 1.5 m tall; leaves less crowded at base, all 

 but the uppermost elongate; panicle 15 to 30 cm long; spikelets 3 

 mm long, the hairs 3 times as long. Ql — Desert regions, western 

 Texas to southern California and Nevada; Mexico (fig. 1603). 



Imperata cylindrica (L.) Beauv. Spikelets 4 to 5 mm long, the 

 hairs as long as in /. hookeri. % — Ballast, Portland, Oreg.; wide- 

 spread in the Old World. 



