PLANT FAMILIES: COMPOSITE. 293 



which are the lonicera and valerian families. The gyncecium of the com- 

 posites presents a highly specialized structure. The ovary is plainly made 

 up of two carpels, as shown by the two styles and the internal structure, 

 but it becomes reduced to a one-seeded achene. From the five carpels in 

 the pyrolas to the composites there is a gradual tendency toward reduction 

 in number of the carpels to two, and in the composites the highest speciali- 

 zation is reached in the consolidation of these into one achene in fruit. 



