698 



FAMILIES OF ANGIOSPERMS. 



is extended on one side into a strap-shaped expansion. To- 

 gether these strap-shaped corollas form the "rays" of the 

 head. The corolla is split down on one side, which permits the 



Fig. 587- Fig. 588. 



Ray flower of Aster no- Tubular flower 

 vaeangliae. of aster. 



Fig. 589. Fig. 590. 



Tubular flower Syngenecious 

 opened to show syn- stamens opened to 

 genecious stamens. show style and two 

 stigmas. 



end then to expand and form the "strap." This is a ligula, 

 or more correctly speaking a false ligula. In fact the ray flower 

 is bilabiate. By counting the "teeth" of the false ligula there 

 are found only three, which indicates that the strap here is 

 made up of only three parts of the 5-merous corolla. The two 

 other limbs of the corolla are rudimentary, or suppressed, on 

 the opposite side of the tube. True ligulate flowers are found 

 in the chicory, dandelion, or in the hieracium, where the five 

 points are present on the end of the ligula. 



The calyx tube in the aster, as in all of the composites, is 

 united with the ovary, while the limb is free. In the aster, as 

 in many others, the limb is divided into slender bristles, the 

 pappus. (In some of the composites the pappus is in the form 

 of scales.) The stamens are united by their anthers into a tube 

 (syngenecious) which closely surrounds the style. (In Am- 

 brosia the anthers are sometimes distinct.) The style in pushing 



