GRAMINEiE. 401 



Palea 2, mostly shorter than the glume, surrounded with a 

 pubescence or long wool at the base ; the dorsal one with or 

 without an awn. Triandria. Digynia. 



1. C. mexicana Nutt. : panicle oblong, loose ; glumes scabrous, pu- 

 bescent, as long as the palese, which are awned on the back ; hairs at 

 the base equalling the palese ; culm and leaves smooth. Arundo cana- 

 dcnsis Mich. Torr. A. cinnoides Muhl. A. agrostoides Pursh. 



HAB. Bogs. N. S. W. to Mich. Aug. U. Culm 3 feet or 

 more high. Leaves long and narrow. Panicle erect, much di- 

 vided. 



2. C. color ata Nutt. : panicle oblong, spiked ; glumes boat-shaped, 

 serrulate ; paleae unequal ; rudiments hairy. Phalaris americana EU. 

 Torr. P. arundinacea Mich. Muhl. 



HAB. Bogs. Can. to Car. Aug. If. Culm 35 feet high. 

 Panicle at length somewhat spreading. 



3. C. canadensis Nutt. : panicle somewhat spiked, conglomerate ; 

 glumes a little longer than the paleee, carinate ; paleae longer than the 

 pappus, awned a little below the tip. dgrostis coarctata Torr. A. 

 glauca Muhl. 



HAB. Bogs. N. S. N. to Subarc. Amer. July, Aug. It. 

 Culm 35 feet high. Panicle stiffly erect. 



4. C. brevipUis Beck : panicle diffuse, capillary ; glumes unequal, 

 shorter than the palese, bearded at the base ; paleae equal, awnless, 

 hairy ; pappus very short. Arundo brevipUis Torr. A. epigeios Muhl. 



HAB. Sandy swamps. N. Y. and N. J. Sept. If. Culm 34 

 feet high. Panicle pyramidal, loose. 



5. C. halleriana De Cand. : panicle loose, glumes acuminate ; dor- 

 sal awn and hairs longer than the paleae, but shorter than the glume. 

 Arundo pseudo'phragmites Schrad. 



HAB. N. S. Schweinitz. 



6. C. confinis Spreng. : panicle lanceolate, spreading ; glumes nerv- 

 ed, acuminate; hairs equalling the palese ; dorsal awn geniculate, 

 longer than the glumes. Arundo confinis Willd. Pursh. 



HAB. Bethlehem. Penn. Schweinitz. 



23. PSAMMA. P. deBeauv. 



Glumes 2-valved, awnless. Palece 2, shorter than the 

 glumes, surrounded with hairs at the base. Scales linear- 

 lanceolate, longer than the seed. Style 3-parted. Stigmas 

 3. Panicle spiked. Triandria. Trigynia. 



P. arenaria P. de B. : panicle spiked ; glumes acute ; pale three 

 times as long as the pappus ; leaves involute. Arundo arenaria Linn. 

 HAB. Sandy shores. Can. and N. S. Aug. If. Roots long, 

 creeping. Culm 23 feet high. Panicle white. 



34* 



