^40 POACE.E. 



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

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

 margins, involute, pungent-pointed, 1-2.5 cm. long. I'auielc erect, 

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

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

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

 l-;j-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 nuicronate, those of the 

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

 about the length of its glume. Nearly allied to M. lyeuroiiles \'asey. 



Mexico, ScJiaffner 1065, PringleMi^; New Mexico, Wright 2017, 

 Palmvr 3" ; Arizona, Pringh, Jones. 



Arizona and Mexico. 



3. M. pulcherrima Scribu. ined. 



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

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

 involute, or conduplicate, 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, l)earing 8-12 spikelets. 

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

 pedicels; empty glumes 1-nerved, rarely 2-uerved, 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, Pringh 1416. 



Dry ledges of jiorphyry. 



4. M. rigida (II. B. K.)Trin. Unifl. 194 (1826). Podoscvmnm 

 rigidiim 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; ligulo 

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



