48 



POACEAE. 



7-25 cm. long; branches scabrous, erect, appressed; spikelets 4-5- 

 flowered, 8-10 mm. long; empty glumes glabrous, the first 2 mm. 

 long or less, second involute, 4-6 mm. long; floral glume ciliate above 

 the middle, awn 5-8 mm. long; palea lanceolate, scabrous on the 

 keels, nearly equaling its glume, with 2 short awns. 



Common on mesas and grassy hillsides, and along streets and 

 waste places. 



8. F. myuros L. Closely resembling the preceding species, but 

 the floral glumes not ciliate. 



Occasional in pastured land. Capistrano. Native of southern 

 Europe. 



36. BROMUS L. Brome-grass. 



Annual or perennial grasses, with flat leaves and ter- 

 minal panicles thickened at the summit. Spikelets few- 

 many-flowered. The 2 lower glumes empty, unequal, 

 acute; flowering glumes rounded on the back or some- 

 times compressed and keeled below the summit. Palea 

 shorter than the glume, 2-keeled. Stamens generally 3. 

 Stigmas sessile, inserted below a hairy cushion at the 

 top of the ovary. Grain adherent to the palea. 

 Annuals. 



Awns evident, 4 mm. long or more. 



Panicle open, the branches spreading. 

 Awn twisted and bent. 

 Awn not twisted and bent. 



Sheaths smooth; awn 4-5 mm. 



long. 

 Sheaths pubescent, awn 30-50 

 mm. long. 

 Panicle contracted and dense. 

 Awns slender, 6-8 mm. long. 

 Awns stout, 16 mm. long or more. 

 Culms smooth. 



Culms pubescent below the pani- 

 cle. 

 Awn inconspicuous, about 2 mm. long. 

 Perennials. 



Spikelets subterete. 



Branches of spikelet stiffly divaricate; 



blades short. 

 Branches drooping; blades elongated. 

 Floral glume pubescent throughout. 

 Floral glume pubescent at margins 

 and base only. 

 Spikelets strongly flattened. 



Blades canescent and densely pilose, 



narrow or involute. 

 Blades not canescent, glabrous or some- 

 what pilose, broader and flat. 



9. 



10. 



B. trinii. 



B. secalinus. 



B. villosus. 



B. hordeaceus. 



B. madritensis. 



B. ruhens. 

 B. unioloides. 



B. orcuttianus. 

 B. grandis. 

 B. laevipes. 



11. B. subveluHnus. 



