GRAMINEAE 23 



Flowering glume not awned. 



Lower glumes acute. 1. M. sobolifera. 



Lower glumes strongly acuminate. 



Flowering glume H /x or more long. 2 M. Mtricana. 



Flowering glume l x/ or less long. 3. M. polbstachya. 



Lower glumes exceeding flowering glumes. 4. M. racemosa. 

 Flowering glume awned. 



Lower glumes minute or wanting. 5. M. diffu.ua. 



Lower glumes to f length of flowering glume. 6. M. tenuiflora. 



Lower glumes equalling flowering glume. 7. M. sylratica. 



1. M. sobolifera (Muhl.) Trin. l-3 high, erect: leaves 3'- 4' 

 long, 2 // -3 // wide : panicle very slender, much-contracted, long-exserted, 

 2 // -6 // long : spikelets l x/ long. Not uncommon in rocky woods. Sep- 

 tember-October. 



2. M. Mexicana (L. ) Trin. Much branching, H-3 high, with 

 geniculate culms : panicles both lateral and terminal, contracted, with 

 appressed spike-like branches, more or less included : spikelets \\ ff or 

 more long ; hairs at base of flowering glume few, short : empty glumes 

 equal or very unequal, longer or shorter than the flowering glume. 

 Common in low woods along streams. August-October. 



3. M. polystachya Mackenzie & Bush, n. sp. 2 high, erect, much 

 branched : leaves 1^-2V long, l // -2 // wide : panicles on peduncles 

 l / -5 / long, long-exserted, 2 / -4 / long, densely flowered, the lower branch- 

 lets separated : flowers nearly sessile, l /x long : the glumes as in the 

 last : hairs at base of flowering glume copious, ^ to 5 length of glume. 

 Open rocky woods east of Sibley. 'August-October. 



4. M. racemosa (Michx.) B.S.P. Culms l-3 high, usually much- 

 branched : panicle terminal, 2 X -4 X long, usually dense and spike-like, 

 exserted, the branches very densely flowered. Bogs and wet rocky 

 woods. Well distributed and rather common. August-October. 



5. M. tenuiflora (Willd.) B.S.P. Distinguished from No. 7 only by 

 its shorter less acuminate, empty glumes. Dry woods near Sibley. 

 A ugust-October. 



6. M. diffusa Willd. NIMBLE WILL. Culms much-branched, dif- 

 fusely spreading or prostrate with numerous short leaves : panicle? 

 slender and contracted, 2 X -4 X long, usually interrupted. Often very 

 common in dry woods. August-October. 



7. M. sylvatica Torr. Culms ascending, l-3 high, bearing a con- 

 tracted panicle 3 / -6 / long. Common in low woods along the larger 

 streams. July-October. 



18. BRACHYELYTRUM Beauv. 



Perennial with erect, pubescent culms and one-flowered spikelets in 

 simple panicles. Glumes three, the first two small and inconspicuous, 

 the outer often wanting. Flowering glume hard, 5-nerved, hairy, long 

 awn-pointed, together with the palet enclosing the grain. Palet as long 



