back. 3 mm. loii^, first and second glumes r)-nerved, the latter 

 wlicu mature with '^-'-i transverse [»lications on each side, third 

 fjlume and palea brown. 



Mexico (Hio Blanco), PaJiiur 408. 



Texas to Florida and Mexico. 



17. P. setaceum Michx. Fl. Hor. Am. 1:43 (180.1). P. eiliati- 

 foJium Michx. Fl. Hor. 1:44 (1S03). /*. debite Michx. Fl. IJor. 

 Am. 1:44 (1803). 



Culms ascending, branching, very slender, 50-70 cm. high, 

 Tjcaves throughout, or the sheaths only, smooth, 5-15 cm. long, 

 ;)-5 mm. wide. Spikes mostly single, terminal, and one or more 

 cxserted or included in the sheaths of the upper leaves, 5-10 cm. 

 long; rachis tlexuose, 1 mm. wide. Spikelets in two or more irreg- 

 ular rows, broud-oval, 2.2 mm. long, first glume 3-uerved, second 

 2-nerved. 



Delaware. Cmifttf 3.5Tfi. 



East Miussachu setts to Illinois and southward. 



Var. ciliatifolium (Michx.) Vasey, Contrib. V. S. Nat. Herb. 

 3:17 (1S!I2). /'. ri/iftfifoliinn Michx. Fl. lior. Am. 1:44 (1S()3). 

 P. dasiiplniUinn VAX. IJot. S. C. and Ga. 1:105 (KSl(i). Cuhns 

 stouter; leaf-blades nmstly longer, 1 cm. wide: spikelets crowded, 

 often appearing in more than two rows, owing to the branching of 

 tlie pedicels of the spikelets. 



Florida. V. S. [hpt. Agricul. 3, from .1. //. Cartiss. 



Southern States. 



IS. P. Humboldtianum Fliigge, :Monog. 07 (1810). 



Culms hard, not fiatteued in drying, exserted, branching below, 

 00-80 cm. long. Leaf-blades numerous, smooth or rough, Hat, 

 Mcuuiinate. 5-1** cm. long, 1-1.5 cm. wide. Spikes 3-4, ajjprox- 

 imate. 8-10 cm. long, rachis 1.5 nnn. wide. S|)ikelets in i)airs, 

 4-rowed, not crowded, pubescent, oval -lanceolate, 3.3 mm. long, 

 first glume with '^ nerves on the margins very close to each other, 

 o\t r 1 mm. long, second glume smooth, 3-nerved, third shorter, 

 oval, obtuse. 



Mexico (Rio Blanco), P(dine)' i»86. 



Mexico to Quito. 



