AVENE.E. 381 



15. T. paniculatum Fourn. Hemsl. Biol. Centr. Am. Bot. 

 3 : 556 (18S0). 



Culms erect, 90-120 cm. high. Blades of sterile shoots sca- 

 brous, involute, 10-20 cm. long, 3 mm. wide. Leaves of the culm 

 scabrous, sheaths shorter than the internodes ; ligule 1-2 mm. long; 

 blades flat or involute, 20-30 cm. long, 3-5 mm. wide. Panicle 

 linear or oblong, rather tliin, 10-25 cm. long, rays in fives, the 

 longest 5-10 cm. long, flower-bearing on the outer half. Spikelets 

 2-flowered, 5-6 mm. long, hairs on rachilla and florets 1 mm. or 

 less in length, first empty glume 3.5-4.5 mm. long, second a little 

 longer; floral glume oblong when spread, 4.3 mm. long, 4-toothed, 

 the awns attached near the middle, 4-5 mm. long; palea as long as 

 its glume. 



Mexico, Pringle 4919, distributed as T. paniculatum Fourn. ? 



Cool pine woods, at an altitude of 9500 feet. 



78. (160). AVENA L. Sp. PI. 79 (1753). Elidotrichon Bess. 

 Andrz. Eys. Botau. 1:9 (1823). HelicotricMum Bess. Eeichb., 

 Fl. Germ. Excurs. 140^ n. 352 (1832). Heuffelia Schur. Euum. 

 PI. Transs. 760 (1866). 



Spikelets few-flowered, rarely 1-flowered, in a loose panicle; 

 rachilla articulate above the 2 outer glumes, hairy under the floral 

 glumes. Empty glumes scarious, at least at the apex, nearly equal, 

 lanceolate; floral glumes smaller, rounded on the back, 5-11- 

 nerved, 2-cleft at the top, bearing a long dorsal twisted awn, the 

 terminal glume often small and empty; palea narrow, 2-toothed. 

 Stamens 3. Styles short, distinct. Grain pubescent or hairy, 

 rarely smooth, frequently adhering to the palea, deeply grooved. 



There are 40 species of annuals or perennials, widely spread over 

 the temperate and cooler regions of the world. 



The genus has been divided into two sections which are quite 

 clearly marked. By cultivation, probably, the dorsal awn of the 

 common oat has been lost or much reduced. 



A. Avenastriim. Perennial; spikelets erect or spreading. 

 Panicle small, narrow, spikelets with more than two per- 

 fect flowers; empty glumes 3-5-nerved (a) 



a. Exotic; awn as long as its glume starting one-tliird 



