EXPEEIMJSNTS WITH PLANTS 



ming over its surface at a high rate of speed, and 

 every footprint is soon carpeted with them. On the 

 plains the Eussian Thistle and other "tumble- 

 weeds " are blown over the level surface of 

 the ground, scattering their seeds at every 

 step (in this case the whole plant assists in 

 the dissemination) . 



The problem of flying is solved in various 

 ways: sometimes the calyx is modified into a 

 parachute (Dandelion, Thistle, etc.) ; some- 

 times the style (Clematis, Fig. 171) is used 

 for this purpose; a bract may serve as a 

 wing (Linden, Fig. 172, and Hop, Fig. 173), 

 or the wall of the ovary may grow out into a 

 flattened wing - like appendage 

 whieS (Maple, Fig. 174), while in other 



by means • j • j i i 



of the cases it IS the seed- 

 feat hery , . 

 style. grows out in this 



(Pines) . Find out what you 

 about this. A very simple 

 way of testing the effec- 

 tiveness of these flying de- 

 vices is to drop the seeds 

 from a height down a stair 

 well or wherever the air is 

 still, and time them in 

 their fall to the earth. 



Are the flying attach- ^^^- Wnden fruit, wWeh flies by means 

 'J ^ of a wing-hke bract. 



