198 



tive" internodes were numerous and large, and the terminal compound umbel, 

 which was small and weak, was built of a mixture of single flowers and umbels of 

 various size; it could not be numbered with any certainty. Hère follows a survey 

 of the lengths of the internodes of this shoot. 



Although the metatopies were very considérable the divergence of the leaves 

 and bracts was still quite normal. By the peculiar distribution of the growth of the 

 stem, the position of the leaves becomes: 1 — 3 scattered, 4 and 5 near together, 

 6 and 8 near together, 7 and 10 at the same level, 9 and 11 near together, 13 and 



16 at the same level and very near a second group composed of 12, 15 and 18; 14 and 



17 together; 19, 20. 21, 23 and 24 together, 26 single, 22, 25 and 27-37 ail in one 

 conglomerate. 



The terminal compound umbel followed close on 37 and was evidently much 

 weakened by the development of 13 strong latéral axes just below it. 



The foregoing observations lead us to the conclusion that in 

 Ferula thyrsillora the original phyllotaxis of the leaves of the shoot 

 is a normal one of the Fibonacci séries; in some cases more regular, 

 in others less. 



By a process of very unlike distributed growth of the différent parts 

 of the stem, the leaves are divided in single leaves, pairs of leaves 

 and greater conglomérâtes; especially higher on, in the upper half 

 of the shoot some true growth whorls are formed in this way. 

 This process has nothing to do with the original phyllotaxis ; whether 

 this was a regular one or not the terminal umbel wiU show in un- 

 altered fashion, as the elcngation has not taken hold hère. 



This growth does not always take place in a certain internode or 

 in some internodes; it is simply a transverse zone of the stem 

 between the originally crowded leaves that stretches itself beyond 

 measure. 



