^58 POACE^. 



Spikelets on pedicels 5-15 mm. long; empty glumes serrulate on 

 the single nerve, second the longer, about 1 mm. long, besides a 

 short bristle; floral glume lanceolate, 3-nerved, 2-3 mm. long, the 

 awn 6-10 mm. long; palea acute, as wide and as long as its glume. 

 Anthers 3 in number, 1.4 mm. long. 



Mexico (Rio Blanco), Palmer 523, 523a. 



38. M. laxiflora Scribn. ined. 



A rather slender erect light green tufted perennial, about 90 

 cm. high. Sheaths shorter than the internodes; ligule thin, lasce- 

 rate, acute, 5-6 mm. long; blades scabrous, involute or condupli- 

 cate, those of the culm 3-4, and 4-15 cm. long, 0.5-0.7 mm. 

 diam. Panicles terminal, thin, purplish, lanceolate (or spreading?), 

 abont 15 cm. long, rays mostly in twos and threes, erect, sparingly 

 branched, bearing 8-15 spikelets on the terminal half. Spikelets 

 on pedicels 1-4 mm. long, empty glumes ovate, acute, obscurely 

 1-nerved, second the longer, 1.5 mm. long, 3-nerved; floral glume 

 scabrid, 3-nerved, 3.7-4 mm. long, linear when spread, acute or 

 bearing a short bristle; palea obtuse when spread, as long as its 

 glume. 



Mexico, Primjle 1412. 



Cool slopes of the Sierra Madre, Mexico. 



39. M. articulata Scribn. Proc. Acad. Phila. 298 (1891). 



An erect densely tufted perennial, 60-80 cm. high. Leaves of 

 sterile shoots nearly as high as the culms; sheaths compressed, 12- 

 18 cm. long; ligule very stout, rigid, 5-7 mm. long; bhules strongly 

 involute or conduplicate, smooth, 0.7-1 mm. diam., long-pointed, 

 articulate at the sheaths, leaving the stout ligule projecting. Pan- 

 icle loosely spikelike, about 30 cm. long, longest rays 3-6 cm. long. 

 Spikelets linear-lanceolate, 4 mm. long; empty glumes lanceo- 

 late, 1-nerved, first 2.5 mm. long, second 3.2 mm. long; floral 

 glume with a tuft of short hairs at the base, 3-nerved, bearing a 

 slender tortuose awn 2-2.5 cm. long. 



Mexico (San Luis Potosi), Pringle 3913. 



On dry calcareous hills. 



40. M. Berlandieri Trin. Mem. Acad. St. Petersb. (VI.) 6.2: 299 

 (1845). 



