POACEAE 



87 



Ptems simple, or sometimes sparinarly branched at the nodes: 

 plants usually bright green : liairs on the leaf-sheaths re- 

 flexed. 

 Spikelets 1.7-2 mm. long : leaf-blades usually pubescent, some- 

 times nearly glabrous, commonly eiliate on the margins. 

 Spikelets about 2.5 mm. long : leaf-blades glabrous, excepting 

 sometimes a few hairs on the margin. 

 Stems at length repeatedly dichotomous-branched, forming dense 

 mats : plants grayishgreen : hairs on the leaf-sheaths, if any, 

 ascending or appressed. 

 Whole plant, excepting the spikelets, glabrous or nearly so, or 

 the sheaths and blades sometimes pubescent. 

 Spikelets broadly obovoid. about 2 mm. long. 

 Spikelets obovoid. 2.-5-3.5 mm. long. 

 Whole plant, including the upper part of the stem, densely 

 villous, 

 b. Leaf-blades widely spreading. 

 B. Leaf-blades of the main stem differing from the above, usually lanceolate 

 to ovate-lanceolate, sometimes short and linear. 

 Stems simple, or rarely a little branched at the lower nodes, forming 

 dense tufts. 

 Leaf-sheaths hirsute. 



Spikelets less than 1.5 mm. long. 

 Sidkek'ts exceeding 1.5jTun. long. 

 Leaf-sheaths glabrous, excepting the eiliate margin : blades strongly 

 and beautifully eiliate on the margins, otherwise glabrous. 

 Spikelets about 1.5 mm. long, glabrous. 

 Spikelets 1.8-2 mm. long, pubescent. 

 Stems finally branching at the upper nodes (sometimes remaining simple 

 in number 89), often repeatedly branching. 

 * >riddle leaf-blades of the main stem less than 1.5 cm. in width, usually 

 less than 1 cm. wide, the base rounded or truncate, sometimes in 

 the broadest ones cordate, 

 t Leaf-sheaths glabrous or puberulent, the lower ones sometimes 

 with a few scattered long hairs, the margins often eiliate. 

 Stem nearly naked above the base, a single leaf above the mid- 

 dle of the stem. 

 Stems leafy. 

 Nodes barbed. 



Spikelets glabrous : 



A little less than 2 mm. long. 

 About 2.5 mm. long. 

 Spikelets pubescent. 

 Xodes naked. 



Spikelets glabrous. 



Spikelets less than 1.5 mm. long. 



Stems densely tufted, less than 3 dm. tall, finally 

 much-branched and prostrate and forming large 

 mats : spikelets about 1 mm. long. 

 Stems exceeding 6 dm. tall : spikelets about 1.3 mm. 

 long. 

 Spikelets 1.5-2 mm. long. 



Leaf-blades eiliate with long hairs, at least for the 



lower half. 

 Leaf-blades not eiliate. 



Primary leaf-blades of the stem large, 9-12 cm. 



long. 

 Primary leaf-blades of the stem small, rarely ex- 

 ceeding 6 cm. long. 

 Leaf-blades widely spreading, thin. 



Stems remaining erect, branching at the mid- 

 dle, the late state assuming the form of 

 a little tree. 

 Stems becoming prostrate, branching their 

 whole length. 

 Leaf-blades erect : 



Thin : stems finally much-branched and pros- 

 trate. 

 Ligule membranous, 0.25 mm. long to al- 

 most wanting : spikelets elliptic. 

 Ligule of erect hairs about 1 mm. long : 

 spikelets obovoid. 

 Firm, the basal ones thick and much broader 

 than the upper. 

 Spikelets 2..5-3 mm. long : 



Elliptic : stems finally much-branched and prostrate. 

 Broadly obovoid : stem.s erect. 

 Spikelets pubescent. 



§ Spikelets less than 2 mm. long. 



Leaf-blades eiliate for at least ]4, their length. 



Panicle ovoid : syjikelets few", 1.75 mm. long : leaf- 

 blades small. 

 Panicle oblong : spikelets nvnnerous. 1.3 mm. long : 

 leaf-blades large. 

 Leaf-blades naked on the margins, or sometimes with 

 a few long hairs at the very base. 



46. P. laxiflonim. 

 45. P. pyriforme. 



47. P. neuranthiim. 



48. P. angustifolium. 



49. P. consanguinexim. 

 107. P. equilaterale. 



42. P. strigosum. 

 46. P. laxiflonim. 



43. P. polycaulon. 



44. P. ciliatitm. 



66. P. midicaule. 



57. P. barbulatum. 



58. P. m iiiojKDttltum. 



59. P. Muttdinuskeetense. 



68. P. Baldmnii. 

 78. P. octonodum. 



52. P. Nashianum. 



56. P. Vadkinense. 



55. P. dichotomtim. 

 62. P. hicidum. 



62. P. lucidum. 



63. P. curtivaginum. 



51. P. Roanokense. 



65. P. sphagnicola. 

 116. P. pernervosum. 



52. P. Nashianum. 

 91. P. erectifolium. 



