GRAMINEAE 23 



Flowering ^lume not awneil. 



Lower fjlunies aonte. 1. 3/. sobolifera. 



Lower filunies stron<j;ly acuminate. 



Flowering jihiine 1 2^^ or more lonij;. 2 3T. Mnticana. 



Flowering yluine \" or less long. 3. 31. poh.stncliya. 



Lower glnmes exceeding flowering glumes. 4. 31. ravemosa. 

 Flowering glume awned. 



Lower glumes minute or wanting. 5. 3T. dlffuf^a. 



Lower glumes ij to if length of flowering glume. 6. 3T. ienuiflora. 



Lower glumes equalling flowering glume. 7. 31. sylratica. 



1. M. sobolifera (Mulil.) Trin. l°-3° high, erect: leaves 3^-4^ 

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

 'if'-Q/' long : spikelets \" long. — Not uncommon in rocky woods. Sep- 

 tember-October. 



2. M. Mexicana (L.) Trin. Much branching, l^°-3° high, with 

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

 appressed spike-like branches, more or less included : spikelets \\" 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 \\'-^)/ long, \"-1" wide: panicles on peduncles 

 V-h' long, long-exserteil, 2''-4^ long, densely flowered, the lower branch- 

 lets separated : flowers nearly sessile, V long : the glumes as in the 

 last : hairs at base of flowering glume copious, \ to \ 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/-\' 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. 

 August-October. 



6. M. diffusa Willd. Nimble Will. Culms much-branched, dif- 

 fusely spreading or prostrate with numerous short leaves : panicles 

 slender and contracted, 2^-4^ 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 '?,'-%' 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 



