316 



Science of Plant Life 



berry, trailing arbutus, laurel, azalea, and rhododendron. 

 The cranberry has long been cultivated on sandy bog lands. 



Blueberries are just coming 

 into cultivation, and much 

 may be expected of them in 

 the future. They grow best 

 on acid soils, and are capable 

 of great improvement in size 

 and flavor through hybridiza- 

 tion and selection. 



The composite family. The 

 composite family is the cul- 

 minating family of the dicots, 

 including more than 12,000 

 species, or nearly one tenth 

 of all seed plants. The dis- 

 tinguishing character of the 

 family is that the small flow- 

 ers are closely grouped in 

 heads, so that the entire 

 flower clusters, in forms like 

 the sunflowers, asters, chrys- 

 anthemums, and dandelions, 

 are often mistaken for single flowers. The calyx-like outside 

 covering is merely several rows of small leaves (bracts) . The 

 whole inner part of the head is made up of many individual 

 flowers, each with its own stamens, pistils, and corolla. Some- 

 times the flowers are all alike, as in the dandelion. Sometimes 

 the outer flowers are petaloid, as in the sunflower, while the 

 inner flowers are tubular and less conspicuous. The floricul- 

 turist has modified the chrysanthemum, aster, and dahlia to 



FIG. 190. 



Mountain laurel, a member of 

 the heath family. 



