TRIANDRIA.— DIGYNIA. 53 



57. ARUNDO. 



A. canadensis: panicle oblong, loose ; glumes sca- 

 brous, pubescent, as long as the corolla ; corolla 

 awned on the back ; hairs at the base equalling the 

 valves ; culm and leaves smooth. 



HAB. Bog-meadows. Aug. If. Cnlm3—4ft.high, 

 mostly simple ; inf. sheaths pubesc. ; pan. purple. 



A. coarctata: panicle somewhat spiked, conglomerate ; 

 calyx a little longer than the corolla, carinate ; co- 

 rolla longer than the pappus, awned a little below 

 the tip. 



HAB. Bog-meadows. July — Aug. If.. Culm 3 — 5 ft. 

 high; pun. straight and erect, never spreading. 



A. brevipilis: panicle diffuse, capillary; calyx un- 

 equal, shorter than the corolla, bearded at the base ; 

 corolla equal, awnless, hairy ; pappus very short. 



HAB. Sandy swamps. Sept. If. Culm 3—4 ft. high, 

 terete ; pan. pyram. loose ; cal. hairy at base. 



58. PSAMMA. 



P. armaria : panicle spiked ; calyx acute ; corolla 

 three times as long as the pappus ; leaves involute. 



HAB. Sea-coast. Aug. y.. Roots long, creeping; 

 culm 2 — 3 ft. high, rigid; pan. cylind. white ; fi. 

 compress. 



59. CRYPSTS. 



C. virginica : spike oblong-cylindrical, thick and 

 lobed ; culm procumbent and geniculate ; leaves at 

 length involute, rigid, pungent. 



HAB. Sandy fields. Aug. — Oct. Culm branched, 

 spreading ; leav.flat, divaric. ; spik. lat. and term. 



GO. ALOPECURUS. Fox-tail grass. 



A. pratensis: culm erect, smooth ; spike cylindrical, 

 obtuse, lobed ; calyx ciliate, somewhat villose, con- 

 nate below the middle ; corolla as long as the 

 calyx. 



HAB. Fie!. Is. June— July. If. Culm 2— 4 ft. high ; 

 leav.jlat; spik. 1 .! in. long; awn twice as long as 

 the flower ; sty I. connate. 



niculutus : culm ascending, geniculate ; spik* 



