18 Class III. Order II. 



water difches. Stem round, smooth, three or four feet high. 

 Leaves very long, smooth, acute. Spikes ten or a dozen, ses- 

 sile, lying over each other, with their backs successively appli- 

 ed to the three sides of a long triangular, smooth, common 

 stalk. Flowers closely imbricated, in a double row, leaning 

 outward, as in the former species. Inner valve of the calyx li- 

 near. Outer valve many times larger, compressed, and to the 

 naked eye glabrous. Through a glass it is found ciliated on 

 the keel. Anthers straw coloured. August, September. Per- 

 ennial. 



DIGYNM. 



20. PANICUM. 

 PANICUM GLAUCUM. L. Glaucous panic 'grass. 



Spike oblong, involucres of many bristles, two 

 flowered ; glumes bearing the seed, undulate-wrin- 

 kled. Mich. abr. 



Culm round, striated, grooved at top. Leaves flat, rather 

 broad, with striated even sheaths and hairy stipules. Spike 

 cylindrical ; flowers commonly in pairs, accompanied by bris- 

 tles of a yellowish green, rough forward. Corolla, inclosing the 

 seed, transversely corrugated. About cultivated and low 

 grounds. July. Annual. 



PANICUM VERTICILLATUM. L. Whorled panic grass. 



Spike whorled ; spikelets in fours ; involucres 

 of two bristles, rough with reversed teeth, and em- 

 bracing a single flower. Sm. 



Culm spreading, rough near the spike. Leaves broad, very 

 rough forward ; stipules hairy. Spike single, rather cylindri- 

 cal, composed of crowded spikelets arranged in whorls. This 

 is readily distinguished from the last and from Panicum 



