ilOKPHOLOGY OF EEPRODTJCTIVE ORGANS 125 



guished from the true corymb by the position of tlie bracts, and 

 by the originally zigzag shape of the sympodiuni. Sometimes 

 the bracts are not developed, when it becomes very difiioult to 

 determine the true composition of this inflorescence. 

 Fig. 237. 



Fi'j. 237. Helicoid cyme of Comfrey iStjmpliii(um officitiate). 



Instances of the scorpioid cyme are found in the Sundew 

 (Drosera), the Rock-rose {Helianthemum), &c. 



Mixed Inflorescences. 



This kind of inflorescence is by no means uncommon. 

 The term is applied to such collections of flowers as show 

 a conjunction of both the types already discussed. Various 

 degrees of complexity can be found, of which the simplest 

 occur when the general inflorescence develops in one way and the 

 partial or individual inflorescences in the other. Thus in some 

 plan-ts of the natural order Compositee {fig. 239), the terminal 

 capitulum is the first to expand, and the capitula, as a whole, 

 are therefore developed in a centrifugal manner ; while the 

 individual capitula, as we have seen, open their florets from 

 the circumference to the centre, or centripetally ; hence, here 

 the general inflorescence is definite, and each partial inflores- 

 cence indefimite. In Labiate plants we have a directly reverse 

 arrangement, for here the individual verticiUasters open their 

 flowers oentrifugally (fig. 191), but the general inflorescence is 

 centripetal ; hence the general inflorescence is here indefinite, 

 while each partial inflorescence is definite. 



