STRUCTURE.] BRAVAIS' IDEAS OF INFLORESCENCE. 325 



binodal cyme one of the nodes is homodromal, the other 

 antidromal. These nodes have usually an unequal ten- 

 dency to develope ; if the homodromal node causes the 

 abortion of its antagonist, the cyme becomes by degene- 

 ration helicoid, and scorpioid in the opposite case. The 

 multinodal cyme offers no fixed rule in the spirals of its 

 nodes ; it generally finishes by degenerating into little 

 binodal few-flowered or one-flowered cymes. We there- 

 fore may consider the binodal cyme as the type of the 

 cymes of dicotyledonous plants. 



10. The helicoid cyme has a straight pseudothallus, not 



excentrical, often vertical. 



11. The scoipioid cyme has its pseudothallus rolled in a 

 plane, excentrical, often horizontal volute, the two rows 

 of flowers regarding the sky. 



12. A cyme may be either axillary or terminal. By de- 



composing the last into partial axillary cymes, we often 

 arrive at the discovery upon the latter of the laws which 

 the entire cyme did not offer. 



13. The multinodal cyme, with axillary cymes, and subject 

 to this decomposition, is sometimes rather difficult to 

 distinguish from the thyrse. If the axillary cymes are 

 one-flowered, there may be a difficulty in distinguishing 

 them from the spike. 



14. Cymes have another method of centrifugal evolution by 

 the development of accessory peduncles ; these peduncles 

 are of the same order as those which are born upon 

 other nodes of the central peduncle, and are almost 

 always antidromal. 



15. Sarmentidia follow in their organisation the same laws 

 as the cyme. 



In this memoir of the Messrs. Bravais there is much which 

 is ingenious; but their system is founded upon theoretical 

 refinements, which require much simplification, before they 

 can be advantageously applied to practical purposes and it 

 can hardly be regarded of such value as to be entitled to 

 supersede the existing well-known nomenclature of the 

 Inflorescence. 



