256 Seed-Scattering 



thistle and many other plants, the wing-like appendages 

 of the seeds of the ash, maple, and sycamore, com- 

 monly called ' keys,' and the long, paper-like leaf-scales 

 attached to the flower-stalks of the lime, which answer 

 a similar purpose; or the wing-hke expansions by 

 which many seeds are themselves bordered, and which 

 act the part of miniature sails. 



The seeds of the water-pink of Ceylon are helped on 

 their way by other means; they are enclosed in circular 

 heads, measuring eight or nine inches across, and 

 beset with elastic spines which stand out in all direc- 

 tions. These heads are detached from the stalks 

 when ripe, and are whirled over the sands for miles, 

 bounding along on the spines, and dropping their seeds 

 by the way. Often, of course, they are whirled into 

 the water, and there they float, the upper spines 

 catching the wind, and acting as sails. 



Water, indeed, plays a most important part in the 

 dispersal of seeds, many of which, if carried only a 

 short distance by the wind to begin with, may con- 

 tinue their journey and travel much further if dropped 

 into river or sea, especially if they happen to reach 

 one of the many ocean-currents. 



There are not many seed-bearing plants which grow 

 actually in the water ; but one of these, the arrow- 

 head, has seeds which keep afloat a long time, not 

 because they are so remarkably light, but because they 

 are so highly polished as to look and behave as if they 

 had been oiled. They do not even become wet, for 

 water runs off them ; and it is not until this polish has 

 been destroyed by much rubbing and long soaking that 

 they can be got to sink. 



The seeds of the water-lilies, white and yellow, are 



