Il8 FLORA. 



Empty scales of the spikelet 1.9 cm. 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. stiiata. 



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



2. A. Stnithiu 

 Empty scales 1.2-1.8 cm. in length, enclosing the flowering scales. 3. A./atua. 



i. Avena striata Michx. Purple Oat. (I. F. f. 393.) Culms 3-6 dm. tall, 

 erect, simple, slender, smooth and glabrous. Leaves erect, 2.5-15 cm. long, 2-6 

 mm. wide, smooth beneath, usually scabrous above ; panicle 6.25-12.5 cm. in length, 

 lax, the branches erect or ascending, naked below, the lower 2.5-6.25 cm. long; 

 spikelets 3-6-flowered, the empty scales smooth, the second 6-7 mm. in length, 3- 

 nerved, the first two-thirds to three-quarters as long, I -nerved; flowering scales 6-8 

 mm. long, with a ring of short hairs at the base, strongly nerved, scabrous; awns as 

 long as the scales or longer. In woods, N. B. to Br. Col., south to northern Penn. , 

 Minn, and Neb. Spikelets reddish purple. July-Aug. 



2. Avena Smithii Porter. Smith's Oat. (I. F. f. 394.) Culms 7.5-15 dm. 

 tall, erect, simple, scabrous. Sheaths shorter than the internodes, very rough; leaves 

 1-2 dm. long, 6-12 mm. wide, scabrous; panicle 1.5-3 dm. in length, the branches 

 finally spreading; spikelets 3-6-flowered; empty scales smooth, the second 6-8 mm. 

 in length, 5 -nerved, the first shorter, obscurely 3-nerved; flowering scales I cm. 

 long, naked at the base, strongly nerved, scabrous, bearing an awn one-fourth to 

 one-half their length. Northern Mich, and Isle Royal. Summer. 



3. Avena fatua L. Wild Oat. (I. F. f. 395.) Culms 3-12 dm. tall, erect, 

 simple, stout, smooth and glabrous. Sheaths smooth, or scabrous at the summit, 

 sometimes sparingly hirsute, the lower often overlapping; leaves 7.5-20 cm. long, 

 2-8 mm. wide; panicle open, 1-3 dm. in length, the branches ascending; spikelets 

 2-4-flowered, drooping; outer scales 1. 8-2. 5 cm. in length, smooth, enclosing the 

 flowering scales; flowering scales 1.2-1.8 cm. long, with a ring of stiff brown hairs 

 at the base, pubescent with long rigid brown hairs, bearing a long bent and twisted 

 awn. In fields and waste places, N. Dak. and Minn. ; abundant on the Pacific 

 Coast. Naturalized from Europe or Asia. July-Sept. 



5 i. ARRHENATHERUM Beauv. 



Tall perennial grasses with flat leaves and contracted or open panicles. Spike- 

 lets 2 -flowered; lower flower staminate, upper perfect; rachilla extended beyond 

 the flowers. Scales 4, the 2 lower empty, thin-membranous, keeled, very acute or 

 awn-pointed, unequal, persistent; flowering scales rigid, 5-7-nerved, deciduous, the 

 first bearing a long bent and twisted dorsal awn, inserted below the middle, the 

 second unawned; palet hyaline, 2-keeled. Stamens 3. Styles short, distinct. 

 Stigmas plumose. Grain ovoid, free. [Greek, referring to the awn of the stami- 

 nate scale.] Six species, natives of the Old World. 



1. Arrhenatherum elatius (L.) Beauv. Oat-grass. (I. F. f. 396.) Gla- 

 brous. Culms 6-12 dm. tall, erect, simple; lower sheaths longer than the inter- 

 in x Us; leaves 6.25-30 cm. long. 2-8 mm. wide, scabrous; panicle I -3 dm. in length, 

 contracted, the branches erect, the lower 2.5-5 cm - ' 1<)T1 sS empty scales finely rough. 

 ened, the second 8 mm. long, the first shorter; flowering scales about 8 mm. Long. 

 In fields and waste places, Me. and Out. to Ga., Tenn. and Neb. Also on the 

 Pacific Coast. Naturalized from Europe. June-Aug. [A. avtnaceum Beauv.] 



52. DANTHONIA DC. 



Mostly perennial grasses, with flat or convolute leaves and contracted or open 

 panicles. Spikelets 3-many -flowered, the flowers all perfect, or the upper stami- 

 nate ; rachilla pubescent, extending beyond the flowers. Scales 5-many, the 2 

 lower empty, keeled, acute, subequal, persistent, generally extending beyond the 

 uppermost Bowering one: flowering scales rounded on the back, 2-toothed. decidu- . 

 OUS, the awn arising from between the acute or awned teeth, flat and twisted at 

 base, bent; palet hyaline. 2-keeled near the margins, obtuse or 2-toothed. Stamens 

 Styles distinct Stigmas plumose. Grain free, enclosed in the scale. [Name 

 in honor of Etienne Danthoine, a Marseilles botanist of the last century.] A genus 

 ul about 100 species, widely distributed, chiefly in South Africa. 



