438 



GRAMINE.E. 



MUHLENBERGIA. 



Rhizoma creeping. Culm 2 feet or more high, much branched, with numerous nodes, 

 often geniculate ; the branches erect, numerous. Leaves 2-3 lines wide, smooth : sheaths 

 compressed, loose. Panicles numerous, elongated, with the branches appressed, exserted or 

 sheathed at the base. Spikelets about 2h lines long, pale green or dull purplish. Glumes 

 rough on the keel, attenuated to a slender point. Paleas either a little longer than the glumes, 

 or about their length, sometimes spotted ; the upper one tapering to a short subulate tip. 

 Stamens 3. Caryopsis cylindrical-oblong. 



Moist meadows, borders of fields, and cultivated grounds : common. August. It is some- 

 times troublesome in gardens ; its widely spreading perennial roots being very difficult to 

 eradicate. M.foliosa, Trin. (Agrostis filiformis, Muhl. gram.) seems to be only a variety of 

 this species. 



18. VILFA. Adans. ; Trin. diss. 1. p. 120. VILFA. 

 Sporobolus, R. Br. Species of Agrostis, Linn. fyc. 



Glumes carinate ; the lower one smaller. Paleas awnless ; the lower one rather acute, longer 

 than the glumes : the upper bicarinate. Stigmas simply plumose. Caryopsis deciduous. 

 — Panicle diffuse, or contracted and spikelike. 



1. Vilfa VAGiNiEFLORA, Torr. Hidden-Jloioered Vilfa. 



Annual. Culms numerous, assurgent ; leaves involute and somewhat rigid ; panicles spike- 

 like, the terminal one more or less exserted, lateral ones concealed in the sheaths ; glumes 

 equal, about as large as the paleos. — Torr. in Gray's Gram. <§• Cyp. part I, no. 3 ; Gray, 

 in ann. lyc. N. York, 3. p. 234. A. Virginica, Muhl. gram. p. 74 ; Torr. fl. I. p. 88 ; 

 Beck, hot. p. 389 ; Darlingt. fl. Cest. p. 57, not of Linn. 



Culms somewhat cespitose, geniculate at the base, simple, rather rigid ; the joints distant. 

 Leaves 2-3 inches long, hairy at the base, slender at the point ; the sheaths swelled with the 

 inclosed flowers : ligule wanting. Panicles oblong, few-flowered ; the branches alternate or 

 in pairs, 1 -2-flowered. Glumes nearly equal, smooth, acute, carinate ; lower one narrowed, 

 lanceolate. Paleae ovate-lanceolate, slightly pubescent, one-nerved ; the lower one shorter 

 than the upper, and about the length of the paleEe. Stamens 3, in the terminal panicles, minute, 

 or wanting? in the lateral ones : anthers purple. Caryopsis about two-thirds the length of 

 the paleas. 



Sandy arid fields and barren hill sides : frequent. September. 



