120 A TEXT-BOOK OF GRASSES 
fications will be discussed in detail later. Unisexual 
spikelets have been mentioned under Par. 144. 
150. Sterile spikelets—Sterile spikelets are those 
which differ from the spikelets with which they are 
associated, in lacking sexual organs. For convenience 
the term is sometimes made to include spikelets that con- 
tain stamens, when such spikelets are the equivalents of the 
sterile ones. In Andropogon the spikelets are in pairs, a 
sessile fertile one and a second pediceled one, which 
in different species may be staminate, empty or reduced 
to the pedicel (Fig. 16). This second or pediceled spike- 
let is generally referred to as the sterile spikelet. In some 
genera in other tribes sterile spikelets occur, usually in a 
definite relation to the fertile ones. These sterile spike- 
lets are prominent in Achyrodes and Cynosurus. In 
Hordeum the spikelets are in clusters of 3, but usually 
the 2 lateral are sterile. In Phalaris paradoza the spike- 
lets are in groups of 7 of which 6 are sterile. Sterile spike- 
lets (when lacking stamens) are sometimes called neuter 
or neutral spikelets. Staminate spikelets, except those 
referred to above which have a definite position and are 
the equivalents of neuter spikelets, should not be called 
sterile spikelets. 
151. The pedicel is the stalk of the individual spikelet 
and represents the ultimate branching of the inflorescence. 
If the pedicel is so short that it is not evident the spike- 
let is said to be sessile. On the other hand the pedicels 
may be elongated and extremely slender as in Orthoclada. 
Sometimes they are slender and nodding, so that the 
spikelets vibrate or tremble in the breeze, as in Briza 
media, the quaking-grass. The pedicel may be jointed 
below the spikelet, in which case the spikelet disarticu- 
lates from the pedicel at maturity. This is true of most of 
