GENUS 53. 



GRASS FAMILY. 



219 



3. Avena Torreyi Nash. Purple Oat. Fig. 

 528. 



Avena striata Michx. Fl. Bor. Am. i : 73. 1803. Not 



Lam. 1783. 

 Trisetum purpurascens Torn Fl. U. S. 127. 1824. 



Not Avena purpurascens DC. 1813. 



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

 and glabrous. Sheaths shorter than the internodes, 

 smooth or slightly scabrous ; ligule ' long or less ; 

 blades erect, i'-6' long, i"-3" wide, smooth beneath, 

 usually scabrous above ; panicle 2i'^s' in length, lax, 

 the branches erect or ascending, naked below, the 

 lower i'-2i' long; spikelets 3-6-flowered, the 

 empty scales smooth, the second 3"-3i" 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, strongly nerved, 

 scabrous ; awns as long as the scales or longer. 



In woods, New Brunswick to British Columbia, Penn- 

 sylvania, Minnesota and Colorado. July-Aug. 



4. Avena Smithii Porter. Smith's Oat. Fig. 529. 



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

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



Culms 2j-5 tail, erect, simple, scabrous. Sheaths 

 shorter than the internodes, very rough ; ligule 2" long ; 

 blades 4'-8' long, 3" -6" wide, scabrous ; panicle 6'-i2' in 

 length, the branches finally spreading; spikelets 3-6-flow- 

 ered ; empty 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 nerved, sca- 

 brous, bearing an awn one-fourth to one-half their 

 length. 



Northern Michigan and Isle Royale. Summer. 



5. Avena Hookeri Scribn. Hooker's Oat. 

 Fig. 530- 



A. pratensis americana Scribn. in Macoun, Cat. Can. PI. 



2: 243. 1888. 



A. Hookeri Scribn. True Grasses 123. 1890. 

 A. americana Scribn. Bull. U. S. Dep. Agr. Agrost. 



7: 183. 1897. 



A glabrous perennial. Culms tufted, 6'-i8' tall, 

 erect ; sheaths keeled ; blades erect, up to 4' long, 

 flat, thick, the midnerve thickened as are the rough 

 margins, linear, acute, those on the culm up to 2" 

 wide, those of the innovations much narrower; 

 panicle contracted, 2'-4' long, its branches erect; 

 spikelets, exclusive of the awns, 6" -7" long, the 

 empty scales acute, scarious above, the second 

 equalling the spikelet or nearly so, the flowering 

 scale 4i"-6" long, brown and firm at the base, sca- 

 rious above the middle, acute, the awn inserted 

 about the middle, about \' long and bent near the 

 middle, spiral at the base. 



On ridges and hillsides, Saskatchewan to South 

 Dakota, west to Alberta and Colorado. June-Aug. 



Avena pubescens Huds., of Europe, reported as adventive in Vermont and New Jersey, can be 

 distinguished by its pubescent foliage and the very long hairs on the rachilla. 



