I io GRAMINEAE. VOL. I. 



Lower empty scales 2. 



Spikes in false whorls or closely approximate ; scales long-awned. 59. Chlorls. 

 Spikes remote, or the lowest only approximate. 



Spikelets scattered or remote in long filiform spikes. 60. Gymnopogon. 



Spikelets crowded in short stout spikes. 



Spikes 4 or less ; spikelets numerous, 25 or more. 62. Bouteloua. 

 Spikes numerous, 12 or more; spikelets few, 12 or less. 63. Atheropogon, 

 2-several perfect flowers in each spikelet. 



Spikelets densely crowded ; spikes digitate. 



Spikes with terminal spikelets. 65. Eleusine. 



Spikes with rachis extending beyond them in a naked point. 66. Dactylocteniitm. 



Spikelets distinctly alternating ; spikes remote. 



Branches of the inflorescence slender ; spikelets less than 2" long, numerous, the 



palets not gibbous. 67. Leptockloa. 



Branches of the inflorescence stout, rigid ; spikelets 4" long or more, few, the palets 



gibbous at the base. 68. Acamptoclados. 



Spikelets with unisexual flowers, very unlike ; plants dioecious. 69. Bulbilis. 



Tribe X. FESTUCEAE. 



Rachilla with hairs longer than flowering scales enveloping them. 71. Phraginites. 



Rachilla and flowering scales glabrous, or if hairy the hairs shorter than the scales. 



Stigmas barbellate ; spikelets in clusters of 3-6 in axils of spinescent leaves. 70. Munroa. 

 Stigmas plumose ; spikelets not in the axils of leaves ; inflorescence various. 



Spikelets of 2 forms, the fertile i-3-flowered, surrounded by the sterile consisting of many 



empty pectihate scales. 91. Cynosurus. 



Spikelets all alike. 



Flowering scales i-3-nerved, rarely with faint additional intermediate nerves. 

 Flowering scales not coriaceous in fruit ; seed beakless and not exserted. 

 Lateral nerves of the flowering scales pilose. 



Internodes of rachilla long, the deeply 2-lobed flowering scale attached by a 



long pointed callus, which is pilose on the outer surface. 75. Triplasis. 

 Internodes of rachilla and callus of flowering scales short, the latter blunt. 



Spikelets on pedicels of varying length, arranged in a contracted or open, 



simple or compound panicle. 

 Inflorescence a contracted or open panicle ; leaf-blades not cartilaginous 



on margins. 73. Tridens. 



Inflorescence a short congested raceme ; leaf-blades with thick con- 

 spicuous cartilaginous margins. 74. Erioneuron. 

 Spikelets on short pedicels of approximately the same length, appressed to 



the long branches of the simple panicle. 77. Diplachne. 



Lateral nerves of the flowering scales glabrous. 



Callus of flowering scale conspicuously pubescent with long hairs. 



Panicle contracted ; flowering scales broadly oval, rounded at the apex. 



79. Rhombolytrum. 



Panicle open, diffuse ; flowering scales lanceolate, acute. 76. Redfieldia. 

 Callus of the flowering scale glabrous. 



Second empty scale very dissimilar from the first, broad and rounded at 



the summit. 81. Sphenopholis. 



Second empty scale similar to the first. 

 Panicle narrow, branches appressed. 



Panicle dull, interrupted ; rachilla articulated. 78. Molinia. 

 Panicle shining, dense, spike-like ; rachilla continuous. 82. Koeleria. 

 Panicle open, the branches more or less spreading. 



Rachilla continuous ; flowering scales deciduous in fruit. 80. Erqgrostis. 

 Rachilla articulated ; flowering scales and palets both deciduous with 



the rachilla internodes. 83. Catabrosa. 



Flowering scales coriaceous in fruit ; seed beaked and exserted. 85. Korycarpus. 

 Flowering scales s-many-nerved. 



Flowering scales 3-toothed at the apex. 72. SiegHngia. 



Flowering scales not 3-toothed at the apex. 



Spikelets with 2 or more of the upper scales empty, broad and enfolding each 



other, forming a club-shaped mass. 84. Melica. 



Spikelets with the upper scales flower-bearing, or if empty similar in-shape to the 



other scales. 



Keels of the palet winged or with a linear appendage. 86. Pleuropogon. 

 Keels of the palet not winged or appendaged. 



Stigmas placed at or near the apex 'of the ovary ; flowering scales usually 



awnless, or awned in nos. 90 and 98. 

 Scales more or less strongly compressed and keeled. 



Empty basal scales 3-6 ; spikelets flat, 2-edged. 87. Uniola, 

 Empty basal scales 2 ; spikelets somewhat flattened. 



Spikelets unisexual ; plant dioecious. 88. Distichlis. 



Spikelets perfect. 



Spikelets arranged in i-sided dense capitate clusters at the end 



of the branches ; flowering scales awned. 90. Dactylis. 

 Spikelets not arranged as above ; flowering scales awnless. 

 Rachilla of the spikelets glabrous, or with webby hairs ; 



flowering scales scarious-margined. 

 Spikelets cordate at the base, large. 89. Briza. 

 Spikelets not cordate, usually small. 



Empty scales projecting beyond the uppermost 

 flowering ones ; arctic grass. 93. Dupontia. 



