

No. 22. 



MUHLENBERGIA DUMOSA Scribn. in Vasey, Contr. Nat. Herb. iii. 71. 



Plant perennial, coarse, from strong rootstock £ inch in diameter. 



Culm erect, robust, giving off fine, solid, woody branches at each node, smooth, 

 shining, 3 to 6 feet high. 



Leaves of culm 10 to 20, mostly reduced to open, yellow, scarious, smooth sheaths, 

 the convolute blades falling early ; leaves of the branches numerous, with slender invo- 

 lute blades 1 to 2 inches long, prominently articulated with the close sheath ; ligule a 

 minute, membranaceous collar. 



Inflorescence numerous loose panicles 1 inch long or less, terminating the rami- 

 fications of the leafy, lateral branches. 



Spikelets nearly sessile or on pedicels less than 1 line long ; empty glumes persist- 

 ent, divergent, ovate, acute, obtuse or bidentate at apex, carinate, membranaceous, 

 except the minutely hispid, green, excurrent midnerve, subequal, § line long; floret 

 caducous, linear, the glume and palet slightly divergent at the apex, equal, 1J lines 

 long; floral glume narrowly ovate, acute, convex, curved backward at the apex, mem- 

 branaceous, ciliate below the middle, prominently 3-nerved, midnerve excurrent in a 

 minutely hispid awn 1 to 2 lines long; palet lanceolate, nearly acute, finely pubescent 

 between the two nerves; grain narrowly cylindrical, reddish-brown, scarcely trans- 

 lucent, roughened, | line long. 



Plate XXII ; a, spikelet enlarged 5 times ; b, empty glumes showing the vari- 

 ation in the apexes; c, floral glume; d, palet. 



Mexico, Arizona and southern California. A strongly rooted, spreading grass. 



