APPENDIX A 



539 



of a naked, pitted general receptacle (gr.). Within are numerous ligulale 

 florets, which are all alike, and have the same number and relation of parts 

 as in the Tubulirlorae. But the split 

 ligulate corolla shows by its five teeth 

 at the distal end that it is composed of 

 five petals. 



The pollination-mechanism is founded 

 on protandry. The elongating style 

 sweeps out the pollen during the first 

 stage of flowering ; the stigma then 

 expands and is receptive during he 

 second stage. The heads expand in 

 sunshine, and intercrossing is possible 

 by many different insects. Self-pollina- 

 tion is also possible by the recurved 

 stigmas coming in contact with pollen 

 adhering to the style. It has, however, 

 been found that in certain cases the 

 fruit of the Dandelion can be matured 

 without any pollination at all, even 

 in buds from which the anthers and 

 stigmas have been all cut away before 

 flowering. 



The fruiting head is the well-known 

 Dandelion " clock." The individual 

 fruit is a dry inferior achene or nut, 

 attached by a long beak to the para- 

 chute-like pappus. These fruits are 

 easily detached by wind, being exposed 

 on the convex growth of the receptacle, 

 owing to the curving back of the invo- 

 lucre (Fig. 445). They are thus scat- 

 tered long distances by the wind. The success of the Compositae as a 

 Family depends largely upon the certainty of each floret producing a good 

 fruit, and on the effective dispersal of the fruit by the wind. 



FIG. 445- 

 Fruit of Dandelion, with pappus as parachute. 



