348 



NATURE-STUDY 



beautiful downy parachutes, which are extensions and 

 modifications of the calyx of the little separate flowers. 

 The calyx in its free upper portion is split up into fine fibres 

 that constitute the parachute. This carries away more than 



a seed. It is a seed plus a 

 close fitting ovary and sur- 

 rounding calyx. Hence 

 it is not merely a seed, 

 but a fruit. Provided 

 with such an excellent 

 device it is no wonder 

 that the composites are 

 so widely dispersed and 

 so abundant. Witness the 

 rapid covering of a burnt- 

 over area with the fire- 

 weed (horseweed). 



Some of the grasses and 

 sedges also have similar 

 silken sails. So have the 

 cat-tails. The Pennsyl- 

 vania anemone has its 

 fruit covered all over with 

 soft down to enable it to 

 float on the air. The fruit of the hairy anemone (pasque 

 flower) and the wild clematis (virgin's-bower) has long hairy 

 '<^ails for the same purpose. 



But in many instances the seed, and not the whole fruit, 

 is provided with wings for dispersal. The milkweed seed 

 illustrates this well. Each has a tuft of silk. So, too, our 

 useful cotton is covered with soft fibres intended for aiding 



Fig. 144. Dandelion Gone to Seed. 



