GRAMINE^. 442 ARUNUO. 



U. aristula'ta. 



CsBspitose ; stems procumbent at base, bearded at the nodes, 10 — 18 inches 

 high ; leaves subulate, tiie upper ones sliorter than tlie sheaths, hairy beneath ; 

 panicles simple, racemose, terminal and lateral, concealed in the sheaths of the 

 leaves, the upper one partly exsert; spilalet 3-flowered ; aicn of the palca as 

 long as the lateral cusps. Sea-coast and sandy fields. Aug. Ann. 



28. AVE'NA. 

 Spikelets 2 — 5-flovvered ; glumes 2, loose and membranace- 

 ous, subequal, longer than the flowers; paieas 2, mostly hairy 

 at base, tlie lower one bitid, with a twisted or bent awn at 

 the back. 



1. A ela'tior. L. Arrhenatherum. Beauv. 

 Stem 2 — 4 feet high, geniculate, smooth ; leaves lance-linear, rough on the 



margin and upper surface ; panicle louse, equal, nodding, branches in pairs or 

 ternate; spikelets 2-flowered ; awn twice as long as the palea ; upper foioer 

 perfect, mostly avviiless. A tall grass, introduced and naturalized in culti- 

 vated grounds. May. June. 



2. A. Pennsyi.va'nica. L. Arrhenatherum. Torr. 

 Stem erect, smooth ; leaves linear-lanceolate ; panicle slender, with short, 



alternate branches ; a%cn twice as long as the flowers, geniculate, from the 

 base of the lower palea ; upper jioictr awnless. Fields and open woods. 

 Rare. July. Ann. 



3. A. pR.5:cox. P.dcB. Aira. L. 

 Ctespitose ; stem erect, a few inches high; leaves i — 1 inch long, rough; 



sheaths deeply striate ; panicle dense, racemose; spihelels ovate, 2-flovvered, 

 glumes as long as the flowers ; lower palea with a bent awn from the lower 

 partof the back twice its length. Ithaca, N.Y. Eaton. Sandy fields. Jn. Ann. 



4. A. SATi'vA. Common Oat. S'^cm smooth, 2 — 4 feet high ; ieai;?* linear- 

 lanceolate, nerved, rough, with loose, striate sheaths; stipule lacerate ; panicU 

 loose ; spikelets pedunculate, pendulous, 2-flowered, both flowers perfect, the 

 lower one mostly awiied ; palea: somewhat cartilaginous, closely embracing 

 the caryopsis. A highly important grain, one of the staple productions of the 

 soil; said to have been first discovered in the Island of Juan Fernandez. Ann. 



yS. nigra ; palca: dark brown, almost black, awnless. Black Oats, 



y. secunda ; panicle \-s\ded ; awns short. Horse-manc Oats. 



5. A. ste'rilis. Animated Oat. Stem?. — 4 feet high, and with the leaves 

 smooth, the latter long, acute, flat; spikelets 5-flowered, outer flowers and 

 awns hairy, inner flowers awnless. From Barbary. Cultivated as a curiosi- 

 ty. The awns are 2 inches long, geniculate, and twisted more or less according 

 to the state of the atmosphere. Hence the tumbling motion of these spike- 

 lets in the moist and warm hands, like a grotesque insect. Ann. 



29. ARU'NDO. 



Spikelets many-flowered ; glumes 2, awnless, lanceolate, 



unequal ; lower flower staminate and naked at base; the others 



perfect, pedicellate; paleae unequal, the lower one mucronate, 



acuminate or slightly awned. 



A. phragmi'tes. 



Siem smooth, stout, erect, G — 12 feet high, often an inch in diameter at 

 base ; leaves lanceolate, 1 — 2 feet long. 1 — 2 inches wide, rough-edged, smooth 

 and glaucous ; panicle large and loosely branched, branches in half whorls, 



