94 Elementary Botany 



one above another are side by side. In this case the younger 

 flowers are towards the centre, and the older ones around them, 

 and hence the indefinite inflorescence is also spoken of as 

 centripetal, or centre-seeking. In the Pink, on the other 

 hand (fig. 147), the stalk is capped by a flower which is the 

 first to open, the younger ones budding below it. This is 

 termed definite inflorescence, or (since, when the flowers are 



Fig. 147. — Diantkus Caryophyllus : portion of Fig. 148. — Simple spike of Ver- 

 plant with definite inflorescence. hena officinalis. 



on the same level, the older ones will be towards the centre, 

 and the younger ones outside) centrifugal. 



Of each of these forms there are several varieties. 



Indefinite or Centripetal Infiorescence. — In the case of 

 tlje indefinite inflorescence the axis may either be lengthened as 

 in the Snapdragon, or arrested as in the Burdock and Dande- 

 lion ; and in either case the flowers may be sessile or stalked. 



A spike is an indefinite inflorescence with a lengthened 



