ORDER CXLII. GRAMINACE^E. 587 



sheaths shorter than the joints, with incised stipules. Glumes unequal, 

 linear-lanceolate, keeled. Palece lanceolate, 3 — 5-nerved. — If. April 

 — May. Upper Carolina and Georgia. 12 — 18 inches. 



4. A. fal'lens, (Muhl.) (Avena palustris, Mich.) Stem erect, genic- 

 ulate at the base, glabrous. Leaves flat, slightly scabrous, narrow ; 

 sheaths glabrous. Glumes compressed, keeled ; the interior valve 

 longest. Palece 2 ; the exterior double the length of the interior, bear- 

 ing a short awn on the back. — If. March — April. Wet soils. Com- 

 mon. 1 — 2 feet. 



5. A. obtusa'ta, (Ell.) Stem erect, glabrous. Leaves flat, somewhat 

 scabrous and hairy ; sheaths hairy. Panicle racemose. Glumes 2 — 3- 

 flowered, the exterior one linear, the interior broad, obtuse. Paleai 

 nearly equal, the exterior tinged with green, the interior white. — If. 

 March — April. Pine-barrens. Common. 



6. A. mollis, (Muhl.) {Reboxdea gracilis, Kunth.) Stem slender, 

 glabrous, naked at the summit. Leaves linear, short. Flowers in race- 

 mose panicles, scattered. Glumes with the interior obtuse, the exterior 

 acute. Paleai acute, the interior shortest, usually 2-eleft. — 2£. April 

 — May. Middle Car. and Geo. Common. 1 — 2 feet 



Gexus XXVI.— AVE'XA. L. {Oat.) 

 (The Latin name.) 



Glumes 2, 2 — 7 -flowered, longer than the florets. Palece bi- 

 laciniate, or with the upper bifid, toothed, with a twisted awn 

 on the back. Seed furrowed. Panicle loose, compound. 



1. A. spica'ta, (L.) (Danthonia spicata, Roem.) Stem erect, pu- 

 bescent near the summit. Leaves subulate, small, pubescent ; sheath 

 with the throat bearded, villous. Flowers pauicled ; spikes racemose, 

 on short pedicels. Glumes usually 6-flowered, longer than the spike ; 

 margins membranaceous. Paleai 2 ; exterior one lanceolate, villous, the 

 sides terminating in two awns, with the spiral one on the back between 

 them ; interior one ciliate. — If. April — May. Upper districts of Car- 

 olina and Georgia. 1 — 2 feet. 



2. A. Pennsylvania, (L.) (Arrhenatherum Pennsylvanicum, Torr.) 

 Resembles the preceding, with the exception that the glumes are 2- 

 flowered, and seeds villous. — New York to Florida. 



3. A. sati'va, (L.) The common oat, the most generally cultivated 

 grain in high latitudes. There are numerous varieties — in the color of 

 the grain or stem, or in the presence or absence of awns, <fec. 



4. A. nu'da, (L.) Is an oat extensively cultivated in Em-ope, which 

 is easily detached from its covering, and is used on that account for 

 grinding into meal, and other culinary purposes. 



Genus XXVIL— U'RALEPIS. Nutt. 

 (From oura, a tail, and lepis, a scale, in allusion to the appearance of the lower palea.) 



Spikelets 2 — 3-flowered ; flowers alternate, longer than the 

 glumes. Palece unequal, villous on the margin ; lower palea 

 3-awned, upper one entire, concave. Stamens 1 — 3. Fruit 

 gibbous, stiped. 



