170 NORTH AMERICAN FLORA 
. XIII MiIcrosTacHya. 
One species. 
XIV. CAESPITOSA. 
Blades less than 1.5 cm. wide ; spikelets 2.2 mm. long or less. 
Spikelets pubescent. 
Racemes commonly less than 5 cm. long; spikelets 1.3-1.8 mm. 
long. 62. 
te play commonly more than 5 cm. long; spikelets 1.8-2 mm. ‘a 
. long. 
Spikelets glabrous. 64. 
Blades up to 2.5 cm. wide; spikelets 2,25-2.5 mm. long. 65. 
XV. LENTIGINOSA. 
Pubescence on spikelets rather scant ; blades commonly less than 1 cm. 
wide ; West Indies and Florida. 
Pubescence on spikelets dense; blades commonly more than 1 cm. 
wide ; Mexico. 
XVI. SCROBICULATA. 
Fruiting scale one half as broad as long or less, elliptic. 68 
Fruiting scale more than one half as broad as long, oval to obovate. 
Spikelets singly arranged. 69. 
Spikelets arranged in pairs. 
Rachis not as wide as the spikelets. 
Low plant, rarely over 3 dm. tall; spikelets orbicular or 
nearly so. 
Tall plant ; spikelets oval, sometimes obovate. 
Rachis wider than the spikelets. 
XVII. PANICULATA. 
Spikelets pubescent. 
Spikelets glabrous. 
XVIII. VirGatTa. 
Fruiting scale white to yellowish. 
Spikelets glabrous. 
Spikelets less than 2 mm. long. 75. 
Spikelets 2mm. long or more. 
Spikelets elliptic to obovate, 2.5-3 mm. long. 76. 
Spikelets nearly orbicular to broadly obovate, 1.8-2.4 mm. long. 77. 
Spikelets pubescent. ; 
Fruiting scale brown at maturity. 
XIX. Dieatata. 
Spikelets about 2.5 mm. long; racemes numerous, usually more than 
10. 
Spikelets 3-3.5 mm. long; racemes few, usually less than 8. 
81. 
XX. FLORIDANA, 
Racemes long and erect, or short and ascending. 
Blades 1-1.5 dm. long; racemes short and ascending. 82. 
Blades 2 dm. long or more; racemes long and erect. 83. 
Racemes long, finally widely spreading. 
Sheaths glabrous ; blades often ciliate with short hairs. 
Sheaths densely hirsute ; blades ciliate with long hairs. 
XXI. MONOSTACHYA. 
Spikelets of 3 scales, the fruiting scale smooth. 
Spikelets, at least the lower one of each pair, of 4 scales, the fruiting 
scale roughened with manifest papillae. 
86. 
Outer convex scale 5-nerved, the internerves about equal in width. 87. 
Outer convex scale 3-nerved, or if 5-nerved the lateral nerves ap- 
proximate and the internerves differing much in width. 
XXII. BIFIDA. 
‘One species. 
XXIII. FIMBRIATA. 
One species. 
XXIV. ORBICULATA. 
One species. 
XXV. ConyjuGATA. 
One species. 
73. 
74. 
84. 
85. 
89. 
90. 
91. 
92, 
[VoLuME 17 
61. P. microstachyum. 
. PB. caespitosum. 
. P. Heltert. 
. BP. glabrum. 
. BP. mandiocanum, 
. P, Simp sont. 
. P. lentiginosum, 
. PL. elatum, 
P. scrobiculatum. 
70. P. convexum. 
71. 
72. 
P. plicatulum. 
P. Boscianum. 
P. paniculatum. 
P. squamulatum. 
P, densum. 
P. Schreberianum. 
P. Underwoodiz, 
78. P. conspersum. 
79. 
P. virgatum, 
80. P. Larrafagai. 
P. dilatatum, 
P. difforme. 
P. floridanum. 
P. giganteum. 
P. longicilium. 
£. monostachyum, 
P. pilosum, 
8. P. unispicatum. 
P. bifidum, 
P. fimbriatum. 
P. orbiculatum. 
P. conjugaium. 
