POACEAE 157 



Flowering scales awnless, or merely awn-pointed. 3. B. inermis. 



Flowering scales with distinct awns. 



Flowering scales glabrous, or pubescent on the margins. 4. B. ciliatus. 



Flowering scales densely pubescent all over the back. 5. B. purgans. 



B. Lower empty scale 3-nerved, the upper 5-9-nerved. 

 Flowering scales rounded on the back, at least below. 



Leaf-sheaths glabrous : nerves of the turgid fruiting scales obscure. 6. B. secalinu?. 



Leaf-sheaths softly and densely pubescent with reflexed hairs : nerves of the 



flowering scales prominent. 7. B. racemosw. 



Flowering scales compressed, keeled. 8. B. unioloides. 



1. Bromus tectorum L. Stems 1.5-6 dm. tall, erect : leaf -sheaths, at least the lower 

 ones, softly pubescent ; blades 2.5-10 cm. long, 2-4 mm. wide, softly pubescent : panicle 

 5-15 cm. long, the branches slender and drooping : spikelets numerous, 5-8-flowered, on 

 capillary recurved pedicels, the flowering scales 8-12 mm. long, acuminate, usually rough 

 or hirsute, the awn 1-1.5 mm. long. 



In fields and waste places, Massachusetts to Indiana, Colorado, Washington, Virginia and Missis- 

 sippi. Naturalized from Europe. Spring and summer. 



2. Bromus st&rilis L. Stems 3-6 dm. tall : leaf-sheaths sometimes pubescent ; blades 

 7-23 cm. long, 2-6 mm. wide, commonly pubescent : panicle 1-2.5 dm. long, its branches 

 usually widely spreading, stiff: spikelets few, 5-1 0-flowered, spreading or pendulous, the 

 flowering scales 7 -nerved, hispidulous on the nerves, the awn 1.5-2.5 cm. long. 



In waste places and on ballast. Locally naturalized from Europe. Summer. 



3. Bromus inSrmis Leyss. Stems tufted, 8-12 dm. tall: leaf -sheaths glabrous; 

 blades 1.5-2.5 dm. long, 4-6 mm. wide, glabrous : panicle 1.5-2.5 dm. long, oblong, its 

 branches ascending : spikelets 2-2.5 cm. long, about 5mm. wide, oblong, erect, the flower- 

 ing scales 10-12 mm. long. 



In fields and waste places, escaping from cultivation, especially in the West. Summer. 



4. Bromus ciliatus L. Stems 7-12 dm. tall : leaf-sheaths retrorsely short-pilose or 

 almost glabrous ; blades lax, 2.5-4 dm. long and about 1 cm. wide, sparsely pubescent, or 

 sometimes nearly glabrous : panicle 1.5-3 dm. long, the lower branches drooping : spikelets 

 5-9-flowered, 15-22 mm. long, the flowering scales 10-12 mm. long, pubescent on each 

 side for about f the length, the awn straight, slender, 3-5 mm. long. 



In woods, Newfoundland to New York, Minnesota and Manitoba. The variety B. ciliatus laevi- 

 gl&mis Scribn. differs mainly in having the flowering scales glabrous, or with a few hairs at the base. 

 Ontario, Maine and North Carolina. Summer. 



5. Bromus purgans L. Stems 7-15 dm. tall : leaf -sheaths usually coarsely retrorsely 

 pubescent; blades 1.5-3 dm. long, 5-15 mm. wide, glabrous, or pubescent on the nerves 

 above: panicle lax, nodding, 1.5-3 dm. long : spikelets 7-11-flowered, 2-2.5 cm. long, the 

 flowering scales 10-12 mm. long, pubescent all over the back, the awn straight, 4-6 mm. 

 long. 



In woods, Canada and New England to Wyoming, Florida and Texas. Summer. 



6. Bromus secalinus L. Stems 3-9 dm. tall : leaf-sheaths commonly glabrous; blades 

 5-23 cm. long, 2-6 mm. wide, sometimes hairy : panicle 5-10 cm. long, its branches as- 

 cending or drooping : spikelets turgid when in fruit, 6-10-flowered, the flowering scales 

 6-8 mm. long, rough toward the apex, awnless, or bearing a straight awn 8 mm. long or 

 less between the obtuse short teeth. 



In fields and waste places almost throughout temperate North America. Naturalized from Europe 

 Summer. 



7. Bromus racemosus L. Stems 3-7 dm. tall, commonly puberulent just below the 

 panicle : leaf -sheaths, at least the lower ones, rather densely pubescent ; blades 7-14 cm. 

 long, pubescent, or sometimes glabrous above : panicle usually simple, sometimes com- 

 pound : spikelets 1.5-2 cm. long, generally nodding in fruit, acute, 5-9-flowered, the 

 flowering scales elliptic, 6-8 mm. long, smooth or rough, the awn 5-8 mm. long, arising 

 just below the apex. 



In waste places, Cape Breton Island and Maine to Pennsylvania and Delaware. The variety B. 

 racemosus commutdtus (Scnrad.) Hook, has the spikelets 2-2.5 cm. long, and somewhat broader flowering 

 scales and the panicle larger. In similar situations and generally distributed throughout the East as 

 far south as Tennessee. Summer. 



8. Bromus unioloides (Willd. ) H.B.K. Annual. Stems 5-10 dm. tall: leaf- 

 sheaths commonly pubescent, or sometimes glabrous ; blades rough, sometimes sparingly 

 pubescent : panicle usually long and narrow, 1.5-5 dm. long : spikelets 2-3.5 cm. long, 

 7-11-flowered, the flowering scales thick, firm, 12-16 mm. long, each commonly with "a 

 short stout awn. 



In waste places, Alabama to Texas and California. Also in Mexico. The variety B. unioloides 

 Haenkeflnus (Presl.) Shear, differs in its smaller size, and almost simple panicle with smaller spikelets;. 

 In similar situations, Florida to Texas and California. Spring and summer. 



