GRAMINACEAE (GRASS FAMILY) 



53 a Panicle narrow, % in. or less broad, often raceme-like 54 

 b Panicle usually more than % in. broad when open.... 55 



54 a Leaves 3 in. or less long 36. Festuca. p 120 



b Basal leaves 4-6 in. long 30. Danthonia. p 7/p 



55 a Awns bent outward and twisted at base 33. Avena. p 120 

 b Awns straight, not twisted at base. ... 37. Bromus. p 120 



56 a Panicle narrow, % in. or less broad, spike-like 57 



b Mature panicle i in. or more broad 58 



57 a Spikelets close together, usually overlapping, hairy 



38. Anthoxanthum. p 120 

 b Spikelets not overlapping, usually much separated, not 



hairy 43. Muhlenbergia. p 120 



58 a Panicle with few stiff branches, the spikelets crowded 



in dense, often i-sided clusters at ends of branches 



39. Dactylis. p 120 

 b Panicles not completely as in a 59 



59 a Spikelets 6- 10- flowered, somewhat flattened 



37. Bromus. p 120 

 b Spikelets i-2-flowered 60 



60 a A conspicuous tuft of hairs at base of inner scale of 



spikelet about as long as the scale 



40. Calamagrostis. p 120 

 b No tuft of hairs as in a 61 



61 a Spikelets 2-flowered ; panicles loose, comparatively few- 



flowered 41. Deschampsia. p 120 



b Spikelets i-flowered; panicles many-flowered 



42. Cinna. p 120 



62 a Plant very hairy throughout, velvety, grayish 



29. Holcus, p 119 

 b Plants not completely as in a 63 



63 a Panicle narrow, % in. or less broad when in flower, 



sometimes spike-like 64 



b Panicle more than % in. broad when in flower with 



branches more or less spreading 68 



64 a Spikelets densely clustered at top of stem, spike-like 



38. Anthoxanthum. p 120 

 b Spikelets not completely as in a 65 



65 a Spikelets i-flowered, comparatively short 66 



b Spikelets 3-i6-flowered 67 



66 a Stems usually swollen at the nodes; leaves usually flat 



43. Muhlenbergia. p 120 

 b Stems not swollen at the nodes; leaves much infolded 



44. Sporobolus. p 120 



67 a Spikelets 3-8-flowered; stems much flattened, bluish- 



green 55. Poa. p 122 



b Spikelets 7-i6-flowered; stems circular; leaves infolded 



45. Distichlis. p 120 



116 



