94 NATUBE-STUDY LESSONS. 



50. (a) What change do you observe in the length of 



the inner bracts shortly before the seeds are 

 matured for dispersal ? 

 ((5) Why do they elongate ? 



51. (a) How long does the flower finally remain closed 



before expanding its sphere of seeds to the 

 wind? 

 (d) What then becomes of the bracts ? 



(c) Why do they so change ? 



(d) Describe in detail the functions served by 



these bracts. 



52. Describe the appearance of the flower when opened 

 for the last time. 



53. (a) Examine the top of the scape on which the 



flowers are placed in a young flower ; alsa 

 this part in flowers opened and with the 

 spherical collection of seeds. 

 (i>) What difference do you observe ? 



54. Account for the seeds with their appendages 

 assuming this spherical form. 



55. (a) What now becomes of the seeds? 



(d) Through what agency are they scattered ? 



(c) In the light of this, account for the lengthening 



of the scape just before the seed dispersal 

 takes place. 



(d) How are the seeds aided in their passage 



through the air ? 



56. Compare the seeds of the dandelion in this respect 

 with the seeds of the thistle, the clematis, the maple and 

 the ash. 



57. Name any other seeds aided in this way by the 

 wind. 



