ATROPHY OF ORGANS FROM TRANSFERENCE 271 



(broom), Spartiwm, Alhagi, etc. The leaves dis- 

 appear, and the stems assume their functions. 



(5) The reduction or disappearance of the calyx. 

 The disappearance of the calyx in many com- 

 posite flowers and of roots in 

 epiphytes are instances of species 

 losing organs because of the 

 transference of function to other 

 organs. 



In the simplest Composite, 

 the fruits (achenes) are dissemi- 

 nated by the wind, the calyx 

 usually being modified into a 

 feathery tuft. In other Com- 

 posite, although wind dispersal 

 still occurs, the feathery calyx 

 is lost, its purpose being fulfilled 

 by wings on the sides of the fruit 

 (Florestinia pedata), or it is united 

 to a large membranous scale 

 developed from the receptacle 

 (Dahlia), or the sterile florets 

 mav be turned into wings (Lind- FIO. so. Branch of JTA- 



lenbeckia platycla<1os. 



heimerw teocana). In other cases 

 the fruits are dispersed, not by the wind, but by 

 animals which eat them (Clibadium asperum), or 

 they adhere to the fur of animals by hooks formed 

 on the achenes (Calendula), or by hooks formed 

 from the involucre of bracts (Lappa). In all these 

 cases, and the list might have been made longer, 



