ORDER CXLII. GRAMINACE^E. 583 



5. A. spicifor'mis, (Ell.) Stem erect, simple, compressed. Leaves 

 linear; sheaths glabrous. Flowers in compound racemes, appressed. 

 Glumes shorter than the palese, terminated by awns. Palece unequal, 

 exterior one 3-awned, with the intermediate one longest, pubescent at 

 the base. — 2£. Sept. — Oct. Pine-barrens. 1 — 3 feet. 



Tribe V.— AGROSTI'DE^E. 

 Spikelets 1 -flowered. 



Giro XVII.— MUHLEXBER'GIA. Schreb. 

 (In honor of Dr. Muhlenberg.) 



Glumes 2, very minute, fringed. Palece ovate, gibbous, much 

 larger than the glumes, the lower one awned. Panicle simple. 



1. M. diffu'sa, (Willd.) Stem decumbent, geniculate, diffuse, com- 

 pressed. Leaves linear, scabrous. Panicle slender, composed of alter- 

 nate, appressed racemes. Glumes* unequal, small. Paleai unequal, 

 pubescent at the base, the exterior 3-nerved; awn purple. — %. July. 

 In fields. 18—20 inches. 



2. 11 polypo'gon*, (Trin.) Leaves convolute, glaucous. Pedicels crowd- 

 ed ; awn longer than the floret ; glumes awned at the apex. — Carolina. 



3. M. capilla'bis, (Trin.) Leaves convolute, long, glaucous. Flowers 

 crowded ; paleae 3 times as long as the glumes ; awns naked. 



4. M. erec'ta, (Pursh.) Stem erect, simple, pubescent. Leaves pu- 

 bescent ; sheath shorter than the joint, hairy at the throat. Panicle 

 loose. Glumes 2, with one very minute. Palece with the exterior one 

 bearing a long awn, many-nerved. — If. July. Rocky hills. 2— -3 ft. 



Genus XVIIL— AGROSTI3. L. 



(From afros, a field ; the place of growth.) 



Glume naked, beardless, 2-valved, 1-flowered ; valves longer 

 than the paleae. Palece 2, membranaceous. Stigmas longitu- 

 dinally hispid. 



1. A. dis'pab, (Mich.) Erect, large. Panicle loose, many-flowered, 

 somewhat verticillate and pyramidal ; the exterior glume the largest, 

 one of the interior very small. — Low country. 



2. A. laxiflo'ra, (Rich.) (Trichodium laxiflorum, Mich.) Stem erect, 

 glabrous. Leaves setaceous, scabrous. Panicles diffuse, capillary, with 

 trichotomous branches. Glumes unequal, lanceolate, acute. Paleai 

 shorter than the glumes, with the margins pubescent. — If. March — 

 May. Dry fields or swamps. 18 inches to 3 feet. 



3. A. ttuchopo des, (Ell.) Stem erect, glabrous. Leaves fiat, sca- 

 brous ; sheath glabrous, with long stipules. Panicle diffuse. Pedun- 

 cles capillary, long. Glumes much shorter than the paleae ; the exterior 

 palea with a short, straight awn, the interior longest. — U- Sept. — 

 Oct. Common. 2 — 3 feet. 



4. A. ar.v hnoi des, (Ell.) (Cinna arachnoidea, Kunth.) Stem erect, 

 Blender, glabrous. Leaves with the sheath as long as the joints. Stip* 



