CHAPTER VII 



THE INFLORESCENCE 



THE inflorescence or ear of wheat is a distichous compound spike, the 

 primary axis bearing two opposite rows of lateral secondary spikelets 



and a single fertile terminal spikelet, except in 

 the case of T, monococcum in which the latter is 

 rudimentary and barren, or missing. 



The main axis or rachis is a sinuous notched 

 structure composed of a number of short inter- 

 nodes (Fig. 76), which in the *' Spelt" wheats 

 T. aegilopoides, T. monococcum, T. dicoccoides, and 

 T. dicoccum disarticulate easily at each node when 

 the ear is ripe (Fig. 77), and in T. Spelta breaks 

 transversely just below each spikelet (Fig. 207). 

 In the majority of cultivated wheats, however, 

 the rachis is tough and resists disarticulation or 

 breaking even when thrashed. 



Each short segment of the axis is narrow at 

 the base and broader at the apex, one side of it 

 being more or less convex, the other flattened or 

 slightly concave. Its lateral edges are fringed 

 with hairs of variable length, and there is usually 

 a larger or smaller tuft of hairs the frontal tuft 

 at the apex of the convex side between the 

 two lowest glumes of the spikelet. All the spike- 



FIG. 76.-Rachis of an ear. lets are sessile ' the lateral ones are ranked 

 a, Rachilla ; b, portion of alternately on opposite sides of the rachis, each 

 rachis with attached spike- bdng placed at the apex of an internode) witn 



its broadside towards the flat or concave surface 

 of the segment immediately above its point of insertion. 



The terminal spikelet is arranged at right angles to the rest. 



Great variety is found among wheats in respect of the number of 

 spikelets per unit length of the rachis. In some, the spikelets are crowded 

 together, the lengths of the internodes between each being very short 



