19 



slightly scabrous, especially below the panicle, puberulent below the glabrous 

 nodes; sheaths shorter than the internodes, striate, the lower ones glabrous, 

 the upper scabrous; ligule 5 to 10 mm. long, acute, cleft at the apex; leaf-blades 

 glabrous, rigid, 1 to 3 dm. long, 2 to 3 mm. wide. Panicles somewhat exserted, 

 strict, purplish, about 1 cm. in diameter; rachis angular, scalirous; branches 1 

 to 2 cm. long, appressed, the lower ones generally remote; pedicels about as long 

 as the spikelets, scabro- 

 pubescent. Spikelets lan- 

 ceolate, 5 mm. long; empty 

 glumes subequal, l-nerved, 

 lanceolate, acute or acumi- 

 nate, 3 to 3.5 mm. long, 

 scabrous on the keel ; flow- 

 ering glume about 5 mm. 

 long, 3-nerved, scabrous on 

 the nerves and keel, bear- 

 ing a rather stout scabrous 

 awn at the apex, 1 to 3 mm. 

 in length. Palea equaling 

 the flowering glume, lan- 

 ceolate, acute, or short-apic- 

 ulate. 



Type collected on lava beds, Ser- 

 rania de Ajusco, altitude 

 3,000 m., Federal District, 

 6675 C. G. Pringle, August 

 13, 1897; Sierra de San 

 Fehpe, altitude 3,000 m.. 

 State of Oaxaca, 4914 C. G. 

 Pringle, September 18, 1894; 

 same locality, C. L. Smith, 

 no number, 1894. 



Muhlenbergia exilis Fourn. 

 Mex. PI. 2: 84 (1881). 



San Francisco, State of Vera 

 Cruz, 1506 C. L. Smith, 1894; 

 Sierra ^ladre Mountains, 

 west of Bolanos, State of 

 Jalisco, J. N. Eose, no num- 

 ber, September 16, 1897. 



Muhlenbergia flaviseta 

 Scribn. U. S. Dept. Agr. 

 Div.Agros.Bul.8: 11 (1897). 



Dos Cajetas, State of Durango, 834 E. Palmer, October, 1896, abundant on the slop- 

 ing sides of an arroyo. 



Muhlenberg-ia gracilis Trin. Gram. Unifl. 193 (1824). 



Sierra de San Felipe, altitude 3,075 m., State of Oaxaca, 928, 937 C. L. Smith, Sep- 

 tember, 1894. 



MuMenbergia implicata Trin. Gram. Unifl. 193 (1824). 



Durango, State of Durango, 718, 769 E. Palmer, September, 1896. 



Muhlenbergia laxiflora Scribn. Zoe, 4: 389 (1894). 



Durango, State of Durango, 2356 J. N. Rose, August 16, 1897. 



MUHLENBERGIA LIGULATA (Fourn. ) Scribn. & Merrill, n. comix ( Chahnis- 

 mca ligulata Fourn. Mex. PL 2: 112, /. — (1881).) 



Fig. 4. — Muhlenbergia densiflor a ^crihn. & Merrill: a. Empty 

 glume; 6, spikelet; r. flowering glume. 



