FORM AND STRUCTURE 



flowers are at the 

 centre, is called a 

 Cyme. 



Umbel, resembles a ra- 

 ceme but the central 

 axis is very short 

 and the pedicels are 

 nearly equal in 

 length. (Fig. 39.) 



Spike, is like a raceme 

 except that the flow- 

 ers are sessile ; they 

 sit directly on the 

 central axis. 



Catkin or Ament, is like 

 a spike except that 

 its bracts are scales 

 and the central axis 

 is often drooping. 

 Flowers of Poplar 

 are examples. 



erect it is called a 

 Th3rrsns. Flowers 

 of Sourwood are 

 borne in a raceme. 

 Corymb, is like a raceme 

 except that the cen- 

 tral axis is shorter, 

 and the lower ped- 

 icels are lengthened 

 so as to bring all 

 the flowers to near- 

 ly the same level. 

 The oldest flowers 

 are at the circum- 

 ference (Fig. 38.) 

 A flower cluster 

 similar in form, but 

 in which the oldest 



Fig. 39. — Umbel of Cherry Blossoms. 

 512 



