240 POACEiE. 



nual, 3-12 cm. high. Sheaths inflated; ligiile variously cleft, 

 1.5-2 cm. long; blades scabrid on both sides, with white thickened 

 margins, involute, pungent-pointed, 1-2.5 cm. long. Panicle erect, 

 narrow, simple, 5-10 cm. long. Spikelets erect, sessile or on short 

 stout pedicels in the notches of the rough, stiff, triquetrous rachis; 

 empty glumes rigid, scabrous, linear-lanceolate, first 2-nerved, 

 1-3-4 mm. long, terminating in two unequal points, second a little 

 longer, lanceolate, awn-pointed, 1-nerved; floral glume smooth or 

 sparingly hairy below, ovate-lanceolate, 3-nerved, 1-3 mm. long; 

 many of those of the sessile spikelets shortly mucronate, those of the 

 pedicellate spikelets terminating in an awn, 2-6 mm. long; palea 

 about the length of its glume. Nearly allied to M. lycuroides Vasey. 



Mexico, Schaffner 10Q5, Pringle^O'^', New Mexico, Wright 2017,. 

 Palmer 3^; Arizona, Pringle, Jones. 



Arizona and Mexico. 



3. M. pTilcherrima Scribn. ined. 



A reddish light green tufted and much-branched diffuse annual, 

 20-40 cm. high. Ligule thin, 2 mm. long; blades scabrid, flat, 

 involute, or condujilicate, 4-6 cm. long, 1-1.3 mm. wide. Pani- 

 cles red, slender, contracted, 6-10 cm. long, rays in threes and 

 very unequal, the longest about 3 cm. long, bearing 8-12 spikelets 

 on the outer two-thirds. Spikelets 1-3 mm. long, on rather stout 

 pedicels; empty glumes 1-nerved, rarely 2-nerved, lanceolate, oval, 

 or sometimes 2-lobed and 2-nerved, first about 0.5 mm. long, 

 second 1.2-1.7 mm. long; floral glume thinly pubescent on the 

 margins of the lower half, lanceolate, 2-toothed, the keel serrulate, 

 3-nerved, 3.5 mm. long, the awn tortuose, 8-16 mm. long; palea 

 linear, almost obtuse when spread, 2.7 mm. long. Anthers 3, oval, 

 0.6 mm. long. 



Mexico, PriNgle 1416. 



Dry ledges of porphyry. 



4. M. rigida (H. B. K.) Trin. Unifl. 194 (1826). Podoscemiim 

 rigidum II. B. K. Nov. Gen. et Sp. 1: 129 (1815). 



An erect glaucous and scabrous tufted perennial, 90-120 cm. 

 high. Sheaths often crowded from the culm, involute; ligule 

 tliin, acuminate, 5-7 mm. long; blades 3, rigid, conduplicate, 30- 



