INFLORESCENCE. 



39 



whilst of the secondary axes (B, B, B), the lowest, being the oldest, flowers first ; and 

 the tertiaries (c, c, c), although often lower than the axis whence they spring, flower 



last. The result is, that of the expanded flowers 

 some are above, some below the buds, according to 

 the order of the succession of their axes. When 

 examining such inflorescences, the student must 

 look for the axis terminated by a flower, for the 

 lateral leaf or bract which it bears, and for 

 the shoot or secondary axis which springs be- 

 tween this axis and itself. 



159. Campanula. Cymose raceme. 



160. Cerastium. 

 Dichotomous cyme. 



161. Hawthorn. Definite corymb. 



The racemose cyme is called a panicle or thyrsus when much branched (Privet] ; 

 but in reality the difference between the definite raceme and panicle is not analogous 

 to the difference between the indefinite raceme and panicle, for the indefinite 

 raceme consists of a primary and many secondary axes ; while the indefinite panicle 

 consists of primary, secondary, tertiary, quaternary axes ; just as is the case both in 

 the definite raceme and definite panicle; the only difference between these two, 

 then, is in appearance. 



The definite raceme becomes a dichotomous cyme., when the primary axis termi- 

 nates in a flower between two opposite leaves or bracts, from the axils of which 

 spring two secondary axes, each again terminated by a flower between two bracts, from 

 the axils of which spring two tertiary axes, and so on (Cerastium, fig. 160) ; this evo- 

 lution of subordinate axes, each terminating between two opposite axes, is continued 

 till the last axis fails, from deficient nutrition, to repeat the process. When, instead 

 of two opposite leaves or bracts, there are three in a whorl below each successive 

 central flower, with again three in their axils, the cyme becomes trichotomous. 



2. In the definite (or true) corymb, the different flowering axes, although of 

 unequal length, attain pretty much the same level (Hawthorn, fig. 161). 



In the definite raceme and the corymb, the central flowers are first developed ; 

 in other words, the flowers open from within outwards, or centrifugally. 



