FLOWER-CLUSTERS 



157 



upwards (Fig. 213). The raceme may be terminal to the 

 main branch; or it may be lateral to it, as in Fig. 214. 



Racemes often bear the 

 flowers on one side of 

 the stem, thus form- 

 V ing a single row. 

 >^ When a cen- 



tripetal flower- 

 cluster is long 

 and dense and 

 the flowers are 

 sessile or nearly so, 

 it is called a spike 

 (Fig. 215). Common 

 examples of spikes 

 are plantain, migno- 

 nette, mullein. 



A very short and 

 dense spike is a head. 

 Clover (Fig. 216) is 

 a good example. The 

 sunflower and related 

 plants bear many 

 small flowers in a 

 very dense and often flat head. Note that in the 

 sunflower (Fig. 189) the outside or exterior flowers 



Fig. 213. — Raceme of Currant. 

 Terminal or lateral ? 



Fig. 214. — Lateral Racemes (in fruit) of Barberry. 



Fig. 215.— 

 Spike of 

 Plantain. 



