58 



PART I. ORGANOGRAPHY. 



cymose plan, whose flowers are sessile, or nearly so, on a short 

 rachis. It resembles a head, but differs from it in the fact that 

 the inflorescence is centrifugal. The Flowering and Canada 



Fig. 190. 



Fig. 191. 

 Fig. 190. — Open cyme of a species of Cerastium. 

 Fig. 191. — Glomerule of the Canada Dogwood. 

 Fig. 192. — Diagram of Scorpioid Cyme. 



Fig. 192. 



Dogwoods both illustrate this form of inflorescence. See Fig. 191. 

 The flower-cluster, as will be seen, is subtended by four con- 

 spicuous bracts, constituting an involucre ; a represents one of 

 the florets of the cluster magnified. 



