104 



POACEAE 



I. Middle blades of the main culm less than 1.5 cm. wide, 

 the base rounded to subcordate. 

 Blades of the main culm usually elongated and nar- 

 rowed at both ends. 

 Plants large; culms 80-100 cm. high; leaf blades 

 11-20 cm. long. 

 Spikelets ovate, 2.5 mm. long or less. 



Sheaths or some of them hispid; autumnal 



form with crowded branchlets. 

 Sheaths glabrous; autumnal form spar- 

 ingly branching. 

 Spikelets elliptic, 3 mm. long. 

 Plants small; culms 40-80 cm. high; leaf-blades 

 scarcely over 9 cm. long. 

 Mature state of blades involute; spikelets 2 



mm. long. 

 Mature blades flat or merely involute on 

 margins; spikelets 2.5 mm. long. 

 Blades of the culm not elongated or conspicuously 

 narrowed at the base. 

 a. Spikelets less than 3 mm. long. 

 Spikelets glabrous. 



Spikelets strongly nerved, acute; blades up 



to 20 cm. long. 

 Spikelets relatively obscurely nerved ; blades 

 rarely exceeding 10 cm. long. 

 Nodes densely barbed; spikelets about 



1.5 mm. long. 

 Nodes naked or rarely the lowermost 

 ones sparingly barbed. 

 Ligule 2-3 mm. long. 

 Ligule short, less than I mm. long. 

 Spikelets 1.5 mm. long. 

 Spikelets 2 mm. long; sheaths 

 not spotted. 

 Culms erect, the branches 

 fasciculate near the 

 middle. 

 Culms prostrate, trailing. 

 Spikelets 2.2 mm. long; sheaths 

 spotted. 

 Spikelets pubescent. 



Sheath glabrous but ciliate, or the basal 

 ones sometimes pubescent. 

 Blades velvety. 

 Blades not velvety. 



Ligule 1 mm. long or less. 



Spikelets less than 2 mm. long. 

 Culms slender, the blades 2.5 



cm. long or less. 

 Culms stouter, the blades 

 larger. 



56. P. scabriusculum. 



57. P. cryptanthum. 



58. P. acideatum. 



21. P. aciculare. 

 20. P. angustifolium. 



56. P. scabriusculum. 



29. P. microcarpon. 



33. P. oclonodum. 

 27. P. coerulescens. 



25. P. dichotomum. 



26. P. lucidum. 



28. P. yadkinense. 



30. P. annulum. 



24. P. ensifolium. 



