STRUCTURE.] BRAVAIs' IDEAS OF INFLORESCENCE. 323 



Flowers placed on distinct stalks, 



arranged upon a lengthened axis. 

 Stalks simple, 



and of equal length, Raceme. 

 the lowermost the longest. 



Inflorescence centripetal, Corymb. 



centrifugal, Fascicle. 



Stalks branched. 



Inflorescence lengthened and 



centripetal. Panicle. 

 depressed and cen- 

 trifugal, Cyme, Verticillaster. 

 arranged upon a depressed axis, Umbel. 



It occasionally happens, as in the Vine, that the axis of 

 some of the masses of inflorescence loses its flowers ; but at 

 the same time acquires the property of twining round any 

 object within its reach, and so of supporting the stem, which 

 is too feeble to support itself. Such axes form what is called 

 a spurious tendril, or a cirrhus peduncularis, and are a striking 

 exception to the general rule that the tendril takes its rise 

 from the petiole or midrib. 



In the preceding account of the inflorescence I have treated 

 the subject in a practical way, and with reference to the usage 

 of Botanists. But the Messrs. Bravais, together with Schim- 

 per and Braun, and some others, led by their examination of 

 the spiral arrangement of leaves into an investigation of the 

 laws that regulate the arrangement of flowers, have proposed 

 a new nomenclature and theory, of which the following is 

 their own abstract (Ann. Sc., N. S., viii. 28.) : 



1. The inflorescence is a union of flowers grouped together 



in mutual relation. It may often be divided into other 

 groups, essentially homogeneous with respect to each 

 other, and which we call partial inflorescences ; these 

 inflorescences may sometimes be themselves subdivided ; 

 but something arbitrary may be sometimes found in the 

 manner of their decomposition. 



2. The flowers, or partial inflorescences which perform the 



Y 2 



