166 PANIC ACE^. 



A reedlike grass 1-2 m. or more high, culms hard. Lignle a 

 fringe of hairs; blades flat, long-pointed, some of the upper 20-30 

 cm. long, 2 cm. wide. Panicle of spikes 60-90 cm. long, consist- 

 ing of 100 or more spikes which are 3-6 cm. long, 10-15 diam. 

 Bristles of the involucre 5-15 mm. long, 25-40 in number sur- 

 rounding each spikelet. Spikelet linear-lanceolate, 5 mm. long, 

 first glume minute, second 1.5 mm. long, third as long as the 

 floret, 5-nerved. 



Mexico, Prmgle 6075. 



Eocky slopes of Mexico. 



7. P. setosum (Sw.) Eich. Pers. Syn. 1:72 (1805). Cenchrus 

 setosus Sw. Fl. Ind. Occ. 1:26 (1797). P. jnirjmrascens H. B. 

 K. Nov. Gen. et Sp. 1:113 (1815). 



Perennial; culms branching, 90-120 cm. high. Sheaths 

 smooth ; ligule ciliate ; blades rough or glabrous, 20-50 cm. long, 

 10 mm. wide. Spike scarcely exserted, cylindrical, dense, about 8-15 

 cm. long, 1 cm. diam., bristles often as long as the single spikelet, 

 with one or more 2-3 times as long, plumose below. Spikelet 

 linear-ovate, 4 mm. long, flrst glume delicate, 2 mm. long, second 

 and floral glume of the neuter floret equal, delicately 5-nerved, the 

 former ovate-cuneate, the latter oval, obtuse, emarginate, or irreg- 

 ularly toothed, palea of the lower floret 3 mm. long, 2-nerved; fer- 

 tile floret smooth, narrowly ovate, 2.5 mm. long, floral glume deli- 

 cately 7-nerved, its palea obtuse, truncate, fringed. 



Mexico (Jalisco), Palmer 677. 



Florida, Mexico, West Indies, Brazil, tropical Africa, East 

 Indies. 



8. P. LONGiSTYLUM Hochst. Flora, 24:1 (1841). I. Intell. 

 19, name only. 



Culms branching, erect, 90-120 cm. high, from a branching 

 rootstock. Sheaths smooth, shorter than the internodes; ligule 

 ciliate; blades flat, hispid, 30-40 or more cm. long, 3-5 mm. wide. 

 Spikes dense, exserted, ovate or oblong, 5-12 cm. long, the short 

 stipes covered with stiff hairs 1-2 mm. long, involucre surrounding 

 a single spikelet, 3-4 cm. long, the bristles plumose for one-third 

 their length, the purple styles projecting for 15 mm. Spikelets 



