THE FLORAL SHOOT. 



431 



These lateral shoots usually branch and elongate so that the 

 terminal flowers on all the branches reach nearly the same height 

 as the terminal flower on the main shoot, forming a somewhat 

 flattened or convex top of the flower cluster. This is illustrated 



A S 



Fig. 453- 



Diagrams of cymose inflorescence. A, dichasium; B, scorpioid cyme; C, heli- 

 coid cyme. (After Strasburger. ) 



in the basswood flower. The anthesis of the cyme is centrifugal, 

 i.e., from the inside outward to the margin. But it is often more 

 or less mixed, since the lateral shoots if they bear more than one 

 flower are dimunitive cymes and the terminal flower opens before 

 the lateral ones. Where the flower cluster is quite large and 

 the branching quite extensive, compound cymes are formed, as 

 in the dogwood, hydrangea, etc. 



831. The helicoid cyme. Where successive lateral branch- 

 ing takes place, and always continues on the same side a curved 

 flower cluster is formed, as in the forget-me-not and most mem- 

 bers of the borage family. This is known as a helicoid cyme 

 (fig. 453, Q- Each new branch becomes in turn the "false" 

 axis bearing a new branch on the same side. 



832. The scorpioid cyme. A scorpioid cyme (fig. 453, B) is 

 formed where each new branch arises on alternate sides of the 

 "false" axis. 



833. The forking cyme is where each "false" axis produces 

 two branches opposite, so that it represents a false dichotomy 

 (example, the flower cluster of chickweed). 



834. Some of these flower clusters are peculiar and it is dim- 



