172 



GRAMIXEAE. 

 44. AVENA L. Sp. PI. 79. 1753. 



Annual or perennial grasses, with usually flat leaves and panicled spikelets. Spikelets 

 2-manv-flowered, or rarely i-flowered; lower flowers perfect, the upper often staminate or 

 imperfect. Scales 4-many (rarely 3); the 2 lower empty, somewhat unequal, membranous, 

 persistent; flowering scales deciduous, rounded on the back, acute, generally bearing a do: 

 awn, the apex often 2-toothed. Palet narrow, 2-toothed. Stamens 3. Styles short, distinct. 

 Stigmas plumose. Grain oblong, deeply furrowed, enclosed in the scale and palet, free 01 

 sometimes adherent to the latter. [Old Latin name for the Oat. ] 



About 50 species, widel3- distributed in temperate regions, chiefly in the Old World. Oats 

 (Arena satira L,.) sometimes appears in waste places or in fields where it has been cultivated. 



Empty scales of the spikelet 6" in length or less, shorter than the flowering scales. 



Flowering scales with a ring of short hairs at the base; awn nearly as long as the scale. 



i. A. stria/a. 



Flowering scales naked at the base; awn not over one-half as long as the scale. 2. A. Smithii. 

 Empty scales of the spikelet 6"-g" in length, enclosing the flowering scales. 3. A. fatna. 





i. Avena striata Michx. Purple Oat. (Fig. 393.) 



Ai'ena striata Michx. Fl. Bor. Am. i: 73. 1803. 



Culms i-2 tall, erect, simple, slender, smooth 

 and glabrous. Sheaths shorter than the inter- 

 nodes, smooth or slightly scabrous; ligule 

 long or less; leaves erect, i / -6 / long, i"-3"wide, 

 smooth beneath, usually scabrous above; panicle 

 2j^'-5' in length, lax, the branches erect or 

 ascending, naked below, the lower i' -2*4' long; 

 spikelets 3-6-flowered", the empty scales smooth, 

 the second 3"-3^" in length, 3-nerved, the first 

 two-thirds to three-quarters as long, i -nerved: 

 flowering scales 3 // -4 // long, with a ring of short 

 hairs at the base, strongl\- nerved, scabrous; 

 awns as long as the scales or longer. 



In woods. New Brunswick to British Columbia, 

 south to northern Pennsylvania. Minnesota and 

 Dakota. Ascends to 3000 ft. in the Adirondacks. 

 Spikelets reddish-purple. July-Aug. 



2. Avena Smithii Porter. Smith's Oat. .(Fig. 394.) 



Avena Smithii Porter; A. Gray, Man. Ed. 3, 640. 1867. 

 Melica Smithii Vasey, Bull. Torr. Club, 15: 294. 1888. 



Culms 2 ;-5 tall, erect, simple, scabrous. Sheaths 

 shorter than the internodes, very rough; ligule 2" 

 long; kavt-s 4'-8' long, $"-6" wide, scabrous; panicle 

 6'-i2' in length, the branches finally spreading; spike- 

 lets 3-6-flowi-rcd; i-mpty scales smooth, the second 

 3"-4" in length, 5-nerved, the first shorter, obscurely 

 3-nerved;. flowering scales 5" long, naked at the base, 

 strongly iu rvi-.i. scabrous, bearing an awn one-fourth 

 to one-half their length. 



Northern Michigan and Isle Royal. Summer. 



