188 



of similar members, arising and developing at the same time, and 

 alternating regularly. 



This distinction, however, was afterwards abandoned by Elchler : 

 many whorls, which arise in spiral order, show afterwards no 

 différences in any respect from real whorls, whereas other whorls, 

 which arise simultaneously take afterwards the characteristics of 

 the spiral system. Other whorls, which are both in their develop- 

 ment and in their adult form undeniably spiral Systems, not- 

 withstanding alternate regularly. In ail thèse respects Eichler 

 found so many transltional stages that he was not able to draw a 

 Ime between both forms, and three years later he was inclined to 

 think that perhaps ail floral whorls were contracted spirals^. 



This view, which has been shared, as mentioned above, by most 

 morphologists, is still corroborated by the fact that leading author- 

 ities in systematic botany hold the opinion that the whorled con- 

 dition in flowers is in gênerai younger, and that the original flowers 

 had only spiral arrangements of their parts. 



In the above lines I hope to hâve made clear m y double aim of 

 consolidating the theory of phyllotaxis and of elucidating the floral 

 morphology. 



For the solution of the problems alluded to, it will be necessary 

 to begin to study the whorled Systems in the végétative régions and 

 the inflorescences. 



For it is only in those régions that we can hope to meet clear 

 conditions. In the flowers the whorls occur in so restricted numbers, 

 and the succeeding whorls differ so much from each other, that 

 the difficulties become too numerous. 



In the végétative régions the conditions are much more stable, a 

 given System may be traced over a good deal of organs, and so there 

 is much more chance to gather some knowledge of the acting causes. 



As we shall see, in the végétative région there are also différent 

 kinds of whorls. I will treat them in separate papers, and this first 

 one will be devoted to a very clear and simple case of false whorls, 

 that I hâve designed as growth whorls. 



1 ibid. II p. XIV. 



