1 6 Flora of the Palonse Region 



Tribe 3. AVENEAE. 



vSpikelets deciduous: lower flower perfect; upper statninate, awued: plant 



velvety. 33. holcus. 



Spikelets not deciduous: empty glumes persistent; flowering ones deciduous. 

 Awn of the flowering glume from between the lobes or teeth, generally 



twisted. 38. DANTHOXIA. 



Awn of the flowering glume inserted upon the back below the teeth. 

 Upper flower perfect; the lower statninate, its glume strongly awned. 



37. ARRHESATHERUM. 



Flowers all perfect; or the upper ones statninate or wanting. 



Spikelets over 12 mm. long: grain furrowed, usually adherent 



to the glumes. 36. a vena. 



Spikelets less than 12 mm. long: grain free, unfurrowed. 

 Flowering glume finely erose-dentate or 2-lobed. 



34. DESCHAMPSIA. 



Flowering glume cleft or 2-toothed, with the teeth some- 

 times produced into awns. 35. trisetum. 



Tribe 4. CHLORIDEAE. 



Rachis produced beyond the upper spikelet: spikelet narrow. 



39. SPARTINA. 

 Rachis not produced beyond the upper spikelet: spikelets globose, some- 

 times 2-flowered. . 40. beckmanxia. 



Tribe 5. FESTUCEAE. 



Flowering glume awned. 



vSpikelets in small fascicles which are united into a densely clustered or 



interrupted panicle. 45. dacTylis. 



Spikelets in panicles or racemes, neither imbricated nor in fascicles. 



Flowering glume rounded on the back, 3-5-nerved; an awn at the 



tip. 48. FESTTca. 



Flowering glume convex or keeled on the back, 5-9-nerved; gener- 

 ally an awn below the 2-cleft tip. 49. bromus. 

 Flowering glume keeled, 3-nerved; a short awn atthe tip, or glume 

 mucronate or bristle-pointed. 43. koki.ERIA. 



Flowering glume not awned. 



Flowering glume I— 3-nerved. 



Rachilla articulated between the flowering glumes. 



43. KOEEERIA. 

 Rachilla articulated below the flowering glumes or not articulated. 



vSpikelets 2-flowered: upper empty glume 3-nerved. 



42. EATOXIA. 

 Spikelets many-flowered: upper empty glume i-nerved. 



41. ERAGROSTIS. 



Flowering glume 5-9-nerved. 



Lower empty glume 3-5-nerved; upper 5-9-nerved. 



44. MEUCA. 

 Lower and upper empty glumes 1-3-nerved. 



Flowering glume keeled. 46. POA. 



Flowering glume round on the back, not keeled. 



Flowering glume obtuse. 47. gi.yceria. 



Flowering glume acute. 48. I'i'.STrCA. 



