THE SPIKELET AND THE INFLORESCENCE 19 



spikelet. The axis, rachis, or branches may be 

 continuous (not jointed), or articulate (jointed) and 

 usually disarticulating (breaking up). The break- 

 ing up takes place at definite points and has to do 

 with scattering the seed. The point of disarticula- 

 tion is the same in grasses of the same kind (or 

 genus) and is usually alike in related genera, and 

 for this reason is of great importance in the classifica- 

 tion of grasses. When there are no joints in the axis 

 or branches, the disarticulation comes in the spikelet, 

 either above the glumes and between the florets or 

 below the glumes. Modifications of these two ways 

 of disarticulating will be met with later. The study 

 of the form of inflorescence and the modification of 

 its parts will be carried on together with that of the 

 spikelet. 



SUMMAKY 



A spikelet consists of glumes and florets, in two 

 ranks and alternate on the rachilla, the florets consist- 

 ing of lemma, palea^ and the inclosed flower. Every 

 organ found in the most highly specialized spikelet 

 is to be interpreted as an elaboration or a reduction 

 of one of these parts. The spikelet is the unit of the 

 inflorescence; the floret is the unit of the spikelet. 

 The spikelet is always simple; that is, the rachilla 

 never branches. The floret is always 1-flowered^ 

 with never more than one lemma and one palea; the 

 glumes and florets are always alternate, two consecu- 

 tive ones never being borne one above the other. 



