92 PAXICACE.E. 



19. P. dilatatum Poir. Lam. Encycl. 5:35 (1804). P. ovatum 

 Nees, Agrost. Bras. 43 (1829). 



Culms 90-130 cm. liigh, simple, smooth. Leaf -blades smooth, 

 30-40 cm. long, 7-9 mm. wide. Spikes 3-7, rather remote, 6-10 

 cm. long, rachis over 1 mm. wide. Spikelets in 4 rows, com- 

 pressed, ovate, acute, pubescent, 3.5 mm. long, first glume 

 5-nerved, second 3-5-nerved, third orbicular, 2.5 mm. long. 



Louisiana, A. B. Langlois. 



Var. decumbens Vasey, Bull. Torr. Club, 13:106 (1886). 



Culms shorter and decumbent. Spikes usually 3-4, 



20. P. pubiflorum Eupr. Bull. Brux. 9, part 2,237 (1842). 

 P. Hallii Yasey and Scribn., Vasey in Bull. Torr. Club, 13:65 

 (1886). 



Culms geniculate and rooting, branching below, nodes pubescent, 

 60-90 cm. high. Ligule firm, 2 mm. long; blades smooth, flat, 10-20 

 cm. long, 0-8 mm. wide. Spikes 3-6, approximate, 2-6 cm. long, 

 rachis 1.7 mm. wide. Spikelets mostly in couples, those in direct 

 lineal line distant about 2 mm., obtuse, finely pubescent, ovate, 

 oval or obovate, obtuse, 2.7 mm. long, first and second glumes 

 3-nerved. 



Mexico (Chihualma), Pringle 374; Texas, Nealley ; Lower 

 California, Palmer 45. 



Alabama to Texas. 



Var. glaucum Scribn., ined. 



Glaucous; culms erect, rigid; sheaths hairy; spikelets more 

 hairy. 



Mexico (Coahuila), Pringle 427. 



21. P. rectum Nees, Hook. Kew Journ. 2 : 104 (1850). P. 

 monostachyum Vasey, Chapm. Fl. S. States, Suppl., 665 (1889). 



A smooth erect perennial, 60-90 cm. high, from creeping root- 

 stocks. Leaf-blades firm, conduiDlicate, 20-60 cm. long, 2-3 mm. 

 wide. Spikes erect, much exserted, mostly single, sometimes two, 

 approximate, 12-20 cm. long, rachis round on the back, sliglitly 

 flexuose, about 1 mm. wide. Spikelets in pairs, those in lineal 

 rank nearly touching each other, smootli, oblong, 2.5-3 mm. long; 



