MORPHOLOGY OF EEPRODUCTIVE ORGANS 123 



produced, the other being suppressed ; this secondary axis 

 behaves like the primary one, bearing only one tertiary axis. 

 This mode of development may be continued for some time, and 

 thus by the coalescence of the successive branches a central axis is 

 produced, which is at first zigzag or curved in shape, but which 

 frequently becomes straightened diiring subsequent growth. 



The bracts of the suppressed axes may be suppressed or not. 

 In any case the true nature of the inflorescence may be ascer- 

 tained by noticing the relation of the bracts to the flowers. In 

 the raceme the flowers are subtended by their bracts ; in the 



Fig. 234. 



Fig. 234. Diagram illustrative of the coustructiou of cymes. A. Tlie 

 diohasium. M. The helicoid cyme. C. D. The scorpioid cyme, a, a\ a-, 

 a^, the successive axes. The fusion of portions of the latter to form the 

 sympodium is indicated by the thickened lines. D represents the con- 

 dition of rafter growth lias sti-aightened the sympodium. 



sympodial cyme there is a bract opposite to the flower upon the 

 axis, showing that the flower is terminal, and the portion of the 

 axis between it and the bract is a part of a sympodium (fig. 235). 



We can distinguish two forms of the sympodial cyme. 



f. The Helicoid Cyme. — This form is produced when the 

 suppression of the successive axes takes place on the same side, 

 causing the sympodium to be curled up in the manner of a helix 

 (fig. 234, B). The successive axes may be developed in a plane 

 at right angles to that of the main peduncle and its first branch, 

 or in one which is parallel to it. Eichler distinguishes the latter 



