138 



FIRST STUDIES IN PLANT LIFE 



9. Hooked seeds. Many seeds, again, cling to 

 animals by the help of hooks. The best known are 

 the common sheep's burr and the Bathurst burr, 

 but there are many others that do not stick so well 

 as these. Such seed-cases cannot fly, nor can they 



jerk out their seed ; but 

 they lie in wait for a 

 carrier. A horse lies 

 down to roll. What a 

 chance to stick a seed 

 on his coat ! A sheep 

 passes on its way to 

 grass 100 miles off. 

 Here is a chance to 

 travel! A boy picks a 

 burr to play at burr- 

 throwing. What a 

 chance to get away to 

 fresh fields ! The mis- 

 chief done by these burr plants is enormous. When 

 the cockle-burr was first noticed in Queensland, £50 

 might have cleared it all out of Australia. Since 

 that time it has cost Australia many thousands of 

 pounds, and no one knows what it will cost in the 

 end. I might give a whole chapter to telling you 

 of the damage done by the Bathurst burr, and how 

 it has spread from land to land. In 1835 a shipload 

 of horses was brought from Chili to Australia. In the 

 tails and manes of the horses were seeds of the bm'r 

 which we now call the Bathurst burr because it was 

 first noticed at Bathurst. It is said that five minutes 

 work would have killed the first few plants that 

 appeared. This would have saved to Australia millions 



Burr-medick (yellow clover). 

 The seed-cases are spirally twisted 

 into a prickly ball. 



