DICOTYLEDONS: CAMPANULALES. 699 



through brushes out some of the pollen from the anthers and 



bears it aloft as in the bell-flower, but the 



stigmatic surface is not yet mature and 



expanded, so that close pollination cannot 



take place. There are usually no stamens 



in the ray flowers. The ovary is composed 



of two carpels, as is shown by the two styles, 



but there is only one locule, containing an Flg " S91 ; 



J Diagram of com- 



erect, anatropous, ovule. posite flower. (Vines.) 



The floral formula for the composite family then is as fol- 

 lows: Ca5,Co5,A5,G2. A number of the composites have only 

 tubular flowers, as in the thoroughwort (Eupatorium) and ever- 

 lasting (Antennaria). 



SUGGESTIONS FOR STUDY OF AN ASTER. 



1186. The aster (Aster novae-anglise). (Some other species may be 

 selected if it is more convenient.) 



The entire plant. Describe the entire plant; the character of the stem; 

 the position of the leaves; their form on different portions of the stem; 

 their attachment to the stem. Compare the "radicle" leaves with the 

 stem leaves. 



The inflorescence. Describe the inflorescence, and the position of the 

 flower heads. 



A single head of flowers. Describe the involucre. What different 

 kinds of flowers are present? What is the position of each kind in the 

 head? Determine the approximate number of each kind of flowers in 

 a head. 



The ligulate flowers. Remove one from the head and sketch it, show- 

 ing the different parts. How many petals are indicated in the strap? 

 How many petals are in the tubular portion of the ligulate flower? Is 

 this a tiUe h'gula? Why? Is the calyx present, and what represents 

 it ? Split open the corolla -tube, and determine whether or not the stamens 

 are present. Is the pistil present in the ligulate flower? 



The tubular flowers. Describe the corolla. How many petals are 

 indicated in the corolla-tube? What is such a corolla called? 



The stamens. Split open the corolla-tube down one side, and sketch 

 to show the position of the stamens, and their relation to each other. Split 

 open the anther column, spread it out, and sketch to show the relation 

 of the stamens to each other, and the pistil within. 



Material. Entire plants in flower; also some of the mature fruit heads. 



The goldenrod (Solidago). (As an alternate, if desired, for the aster.) 



