44 PLANT LIFE. 



the bracts which surround the small florets and make a 

 sort of palisade round them is shortly curved back into 

 a . strong, though small hook. In South America 

 another Composite, Xanthium, with an even more 

 perfect system of clinging spiny bracts, is sometimes 

 very troublesome. By its fruits the manes and tails of 

 horses are sometimes so thickly felted together that 

 they seriously interfere with the animals' movements. 



On the other hand a Composite very common 

 abroad but rather rare in Britain, Bidens, produces 

 three very peculiar harpoons on the fruit. Each of 

 these is a short stiff hair, with two or three very 

 distinct backward pointing parts, like the barbs of an 

 arrow. They are well adapted to stick in the fleece of 

 an animal ; in this case each fruit travel^ separately. 



Perhaps the most beautiful of all these arrangements 

 is that found in the fruit of the common Avens, Water 

 Avens, and also in the garden species of Geum. Here 

 there are numerous carpels which, when ripe, harden 

 into separate dry one-seeded " achenes " ; each of these 

 ends above in a slender yet strong spine, which has a 

 very neat S-shaped curve nearly at the tip. The sharp 

 point runs into cloth, fur, or feathers, and the little 

 curve makes it certain that the fruit will be carried off. 

 The grass Setaria is remarkable for its barbed hairs, 

 which are really the stalks of suppressed flowers, and 

 are only of use in carrying the fruit about. 



A very rare British plant, Linnaea borealis, has its 

 fruit covered with little sticky hairs, which cling to a 

 passing animal. The seeds of Brook lime ( Veronica 

 beccabunga) are covered with a fine gummy layer. 

 The capsules only open in water and the seeds drop 

 into the mud. They are in all probability carried 

 off on the feet or feathers of marsh birds of various 



