GRAMINE^E. (GRASS FAMILY.) 409 



16. MTJHLENBEKGIA, Schreb. DROP-SEED GRASS. 



The grain is lance-oblong and drops enclosed in the palets. 



* Panicles contracted or glomerate, 

 - Flowering glumes barely mucronate or sharp-pointed. 



1. M. Mexicana, Trin. Stems ascending, much branched, 2 to 3 feet 

 high : leaves short and narrow : panicles lateral and terminal, often included 

 at the base, the branches densely spiked-clustered, linear : outer glumes awn- 

 less, sharp-pointed, unequal, the upper about the length of the very acute 

 flowering glume. Wyoming and eastward, where it is very common. 



i- -i Flowering glume bristle-awned from the tip. 



2. M. Wrightii, Vasey ined. Stems erect, 9 inches to a foot high or 

 more: leaves involute, rather rigid and pungently pointed, scabrous, pale; 

 sheaths much shorter than the internodes : panicle spike-like, I to 3 inches long, the 

 two or three lowest clusters of spikelets somewhat distant : the glumes and 

 palets scabrous, especially on the midribs ; lower glume the shorter, J to ^ the 

 length of the flowering glume, mucronate pointed ; upper glume longer, l-nerved 

 and short-awned : Jlowering glume l-nerved, tipped bj a stout rough awn about 

 % the length of the palet. Colorado and New Mexico. 



3. M. gracilis, Trin. Stems erect, rigid, clothed below with withered 

 sheaths, 6 inches to 2 feet high : leaves filiform, convolute, scabrous, with the 

 whole plant pale ; sheaths longer than the internodes : panicle 3 to 6 inches long, 

 often bronzed or blackish, very narrow, the erect rays mostly solitary : lower 

 glume a little the shorter, more or less acute ; the upper half the length of 

 the floret, 3-nerved, obtuse, erose at apex or with several teeth, some of them with 

 short awns : flowering glume with a short-bearded minute callus, pubescent, 

 often thickly marked with blackish-green spots, terminated by a slender rough- 

 ish awn 4 to 9 lines long. Colorado and southward, thence westward into 

 California. 



Var. breviaristata, Vasey. Cespitose, low, often growing in ring-like 

 patches : leaves very short and rigid : panicle short, 2 or 3 inches long, very 

 close : aivn about the length of the Jlowering glume. Rothrock, in Wheeler's Rep. 

 vi. 284. Colorado and eastward. 



4. M. sylvatica, Torr. & Gray, var. setiglumis, Watson. Stems a 

 foot high, nearly erect : panicle contracted into a glomerate spike ; the branches 

 solitary and densely flowered, mostly to the base : outer glumes attenuate into 

 a scabrous bristle : flowering glume with its awn about twice longer. Bot. King 

 Exped. v. 378. Colorado and Nevada. . 



5. M. comata, Benth. Stems 1 to 3 feet high, smooth except at the nodes 

 where they are retrorsely pubescent : leaves flat, roughish on both sides ; lower 

 sheaths equalling the internodes, the upper somewhat shorter: panicle 3 to 

 4 inches long, pale green, lead-colored or purplish, either narrow throughout 

 or lobed below, the lower rays 2 or 3 together, the upper solitary, all very 

 densely many-flowered : outer glumes narrow, very acute, the lower a little the 

 longer, serrulate on the keel : floret with an oblique callus bearing hairs as long as 

 the floret: Jlowering glume 3-nerved, with a long (3 to 4 lines) , Jlexuose, rough, often 

 purplish awn. Vaseya comata, Thurb. From Nebraska to Colorado, Nevada, 

 and California. 



