A MANUAL OF HOTANY 



77 



the flowers may be Hat in form (as in the dandelion). For 

 proper study a lens is a necessity. The collection of flowers 

 surrounded by the involucre is called a " head." 



Study the head for size and color of each of the above 

 parts, observing the difference, if any, in color of disk and 

 ray. Determine the number of ray and disk flowers, at least 

 approximately. Look at the bracts of the involucre, and 

 observe the form, number, and arrangement. The student 

 is very apt to consider the involucre a calyx and so designate 

 it. Be careful about this. 



The individual disk and ray flowers. Study each form care- 

 full}' (m), particularly the disk flowers. On the latter, find 

 a tiny seedlike ovary below, a cluster of fine hairs {pappus 

 calyx) just above, and above the latter a tube ending in five 

 teeth (petals). Projecting from the tube is a forked style, 

 closely invested by five anthers. 



Drawings. Make the following drawings : side and face 

 views of the compound flower, a single ray and a single disk 

 flower (m), and a plan of the compound flower. 



Problems. Why are the flowers of this family so numerous 

 in species and individuals ? What common devices for pol- 

 lination have been perfected ? For seed distribution ? Why 

 is this family considered the highest in the plant scale ? 

 (See No. 22.) 



Useful applications. Make a table of useful and ornamental 

 plants belonging to the tubular forms of the family, using 

 the form given below as a guide. 



Plants for Food with Ediki.k 



Roots 



Leaves 



Stems 



Flowers 



Plants for 

 Ornament 



Plants for 

 Medicink 



