MORPHOLOGY OF THE FLORAL ORGANS 113 
culms produce foliage-branches some or all of which may 
end in an inflorescence. 
The unit of the inflorescence is the spikelet, which 
consists of one or more flowers with the subtending floral 
bracts. The common forms of inflorescence are the spike, 
the raceme and the panicle. 
143. Kinds of inflorescence——The spike—tThe spike- 
lets are sessile along an elongated axis. Familiar examples 
of this form are the members of the tribe Horde, as 
wheat and rye (Figs. 57-62). 
The raceme-—tThe spikelets are pediceled and borne 
along an elongated axis. Simple forms of meadow fescue 
and sheep’s fescue show racemes. The individual inflo- 
rescence of Paspalum is apparently a spike, but really a 
spike-like raceme. 
The panicle—The spikelets are pediceled and the 
inflorescence is repeatedly branched. The oat- and blue- 
grass are familiar examples (Fig. 54). 
Mized inflorescences——True spikes, except in the Hor- 
dez, are rare, as is also the simple raceme. An inflores-— 
cence that is apparently a spike often shows that the 
spikelets are not sessile but more or less pediceled. Such 
an inflorescence is properly a spike-like raceme. Similarly 
a panicle may be so contracted that the pedicels and short 
branches are hidden and the inflorescence appears to be 
a spike, but in precise language should be called a spike- 
like panicle (Fig. 38). 
The component parts of the inflorescences of the genera Pas- 
palum and Syntherisma (e.g., crab-grass) are spike-like racemes. 
The so-called spikes or heads of timothy and canary-grass are spike- 
like panicles. 
In the genus Andropogon what appears to be a spike consists 
of a jointed axis, each joint bearing a pair of spikelets, one sessile 
H 
