52 POACEAE 
TRIBE IX. AVENEAE. 
Spikelets readily deciduous as a whole. : : 68. HoLcus. 
Spikelets with the cd be scales persistent, the flowering scales deciduous. 
Spikelets 2-flowered : rachilla not rolonged. 69. AIRA. 
Spikelets 2-many-flowered : rachilla extending beyond the upper flower. 
Flowering scale awned below the teeth. 
Flowers all perfect. ; 
Grain free, unfurrowed : spikelets less than 1 em. long. 
Flowering scales erose-toothed or shortly 2-lobed at the apex. 70. DESCHAMPSIA. 
Flowering scales cleft or 2-toothed, the teeth extending into 
awns. 71. TRISETUM. 
Grain furrowed, adherent to the scale: spikelets exceeding 1 cm. 
in length. 72. AVENA. 
Flowers different, the uper perfect, the lower staminate and with its a 
scale strongly awned. 73. ARRHENATHERUM. 
Flowering scales awned between their usually awned teeth. 74. DANTHONIA. 
TRIBE X. CHLORIDEAE. 
A. Spikelets with perfect flowers. a 
Spikelets deciduous as a whole. i 76. SPARTINA. 
Spikelets with at least the empty scales persistent. 
Spikelets with one perfect flower. 
No scales above the flowering scale. 
Spikes 2-6, digitate. 75. CAPRIOLA. 
Spikes numerous, arranged along a common axis. 82. SCHEDONNARDUS. 
1-several scales above the flower. 
Empty scales 4. 77. CAMPULOSUS. 
Empty scales 2. 
Spikes in whorls or closely approximate. 
Flowering scales with a single awn or awnless. 
Second empty scale acute: awn of flowering scales usually 
long. 78. CHLORIS. 
Second empty scale truncate or 2-toothed : flowering scales 
awnless or awn-pointed. 79. EUSTACHYS. 
Flowering scales with three awns. 80. TRICHLORIS. 
Spikes scattered. 
Spikelets scattered or distant. 81. GYMNOPOGON. 
Spikelets crowded. 
Spikes generally 4 or less, rarely as many as 8, long : spike- 
lets numerous, exceeding 12. 83. BOUTELOUA. 
Spikes often numerous, short: spikelets few, less than 12. 
Rachis of the spikes with manifest internodes. 
Spikelets broad, erowded ; internodes of the rachis 
short: rachilla terminated by a 3-awned scale, 
or sometimes reduced to 3 weak awns. 84. ATHEROPOGON. 
Spikelets very narrow, scattered : internodes of the 
rachis at least 14 as long as the spikelets: ra- 
chilla terminated by 3 stout awns. 85. TRIATHERA. 
Rachis with the internodes so short that the spikelets 
; appear clustered. 86. POLYODON. 
Spikelets with 2-3 perfect flowers. 
Spikes commonly digitate ; spikelets crowded. 
Spikes with terminal spikelets. 87. ELEUSINE. 
Spikes with the rachis extending beyond the spikelets in a manifest 
: f ege : 88. DACTYLOCTENIUM. 
Spikes distant: spikelets alternate. 
Spikelets small, numerous and crowded : scales thin. 89. LEPTOCHLOA. 
À Spikelets large, few and distant: scales firm and thick. 90. ACAMPTOCLADOS, 
B. Spikelets dioecious, those of the two sexes very dissimilar. 91. BULBILIS. 
TRIBE XI. FESTUCEAE. 
Flowering scales many-cleft into awn-like divisions. 92. PAPPOPHORUM. 
Flowering scales entire, or at most 2-lobed. 
Hairs on the rachilla or flowering scale very long and enclosing the latter : 
tall reed-like grasses. 
Flowering scales hairy : rachilla glabrous. 95. ARUNDO. 
Flowering scales glabrous: rachilla hairy. 96. PHRAGMITES. 
Hairs, if any, on the rachilla or flowering scales shorter than the scale: 
rasses of lower stature. 
Stigmas barbellate, on elongated styles. z 
Spikelets dioecious, single, concealed in the heath-like leaves. 93. MONANTHOCHLOE. 
_Spikelets perfect, commonly in 3's, in the axils of stiff spinescent leaves. 94. MUNROA. 
Stigmas plumose, sessile or on a short style. 
Flowering scale 1-3-nerved, or rarely with faint additional interme- 
diate nerves. 
adesse: nue membranous : seed not beaked nor exserted from 
e scale. 
Lateral nerves of the flowering scale pilose. 
Internodes of the rachilla long, the deeply 2-lobed flowering 
scales attached by a long pointed callus. 99. TRIPLASIS. 
Internodes of the rachilla and the blunt callus of the flower- 
ing scale short. 
Inflorescence simple or pe iiir contracted or open, the 
spikelets on pedicels of varying length. 
