COMPOSITE FLOWERS 



25 



and many other plants belong, that have their many small flowers 

 grouped in a compact head as shown at A in Figure 23. This 

 group of plants is called Composites, and includes some of our 

 useful plants as well as some of the most troublesome weeds. 



Fig. 25. — A cluster of Lady's-slippers. 



Both calyx and corolla are somewhat peculiar. In some cases, 

 as in the Sunflower, the flowers occupying the center of the head 

 have tube-hke corollas and are called tubular flowers, while those 

 around the margin have strap-shaped and much more showy 

 corollas, and are called ligulate flowers. See A, B, and C of 

 Figure 23. In some of the Composites, as in the Dandelion, all 

 of the flowers of the head are ligulate, while in some, like the 

 Thistle, all the flowers are tubular. The calyx is often composed 



