190 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Spikelets articulated below the glumes; 
spikes several, racemose........... 
Spikelets not articulated below the 
glumes. 
Spike solitary. ..........0..000..00.. 
Spikes few, digitate................. 
Spikelets bearing sterile lemmas above the 
fertile floret. 
Spikes solitary or approximate. 
Sterile lemmas below the fertile 
Sterile lemmas below the fertile 
floret none. 
Fertile lemma 1l-awned or awnless.. 
Fertile lemma 3-awned............. 
Spikes several, racemose. 
Spikelets usually numerous, normally 
all alike; spikes usually oblong 
or linear... 2.22... 
Spikelets 1 to 3, normally of two forms 
in each spike (usually alike in 
Pentarrhaphis polymorpha); spikes 
triangular in outline. 
Spikelets 2, one of them reduced toa 
cluster of awns (or both devel- 
oped in P. polymorpha); sterile 
floret 1.2.2.2... cece eee eee 
Spikelets 3, the lateral staminate or 
rudimentary, smaller than the 
terminal; sterile florets 2 or more 
Spikelets paniculate or spicate, but not in one- 
sided spikes. 
Spikelets sessile on opposite sides of a zigzag 
jointed channeled rachis forming a spike. 
Plants dicecious; fertile spike corniculate... 
Plants not dicecious. 
Spikelets solitary at each node of the rachis. 
Spikelets placed edgewise to the rachis. . 
Spikelets placed flatwise to the rachis... 
Spikelets 2 or 3 at each node of the rachis, 
Spikelets 1-flowered, not all alike, the 
Spikelets 2 to 6-flowered, all alike. 
Axis of spike continuous, not disar- 
ticulating at maturity; glumes 
broad or narrow but not greatly 
elongated............00..2.... 
Axis of spike disarticulating at ma- 
turity; glumes setaceous, elon- 
gated... 2... ee. 
Spikelets in open or spike-like panicles. 
84. 
82. 
83. 
85. 
86. 
87. 
88. 
90. 
89. 
125, 
124. 
126. 
127, 
128. 
129. 
SPARTINA (p. 329). 
MicrocHLoa (p. 328). 
CAPRIOLA (p. 329). 
CAMPULOSUS (p. 330). 
CHLORIS (p. 330). 
TRICHLORIS (p. 334). 
BouTELova (p. 335). 
PENTARRHAPHIS (p. 346). 
CATHESTECUM (p. 345), 
JOUVEA (p. 384), 
Lourum (p. 383). 
AGROPYRON (p. 384). 
Horpevo (p. 385). 
Exymus (p. 385). 
SITANION (p. 386). 
