LESSON II 

 THE SPIKELET AND THE INFLORESCENCE 



THEORETICALLY the spikelet is a reduced leafy 

 branch. In the generalized spikelet shown in Fig. 8 

 the likeness to a jointed culm with 2-ranked leaves 

 (Fig. 1) is readily seen, the glumes and lemmas corre- 

 sponding to sheaths, their blades not developed. The 

 palea, with two nerves and with its back to the axis, 

 corresponds to a minute bract (the prophyllum) 

 borne at the base of a branch in the axil of a sheath. 

 The prophyllum is always 2-nerved, with its back 

 (that is, the space between the nerves) against the 

 main axis and its margins clasping the young branch. 

 The flower, also, is theoretically an ultimate branch- 

 let. In the flower-bearing lemmas, therefore, the 

 palea is developed, while in the glumes, bearing no 

 flowers, there are no paleas. Glumes and lemmas 

 are, morphologically, reduced leaves, the lower pair, 

 not flower-bearing, being termed glumes, the flower- 

 bearing ones being termed lemmas. (See Fig. 7.) 



The jointed axis of the spikelet (the rachilla) 

 corresponds to the jointed culm and, like it, usually 

 breaks at the nodes, the internode (the part of the 

 rachilla between two nodes) remaining attached to 

 the floret at its base (Fig. 4), just as in a broken 

 grass stem the internode of the culm remains with 



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