48 PLANT LIFE. 



The broad concave bracts of the Hop contain a single 

 fruit, protected by peculiar little yellow glands which 

 prevent animals from eating it Each bract is blown 

 off by itself and carries the fruit to a considerable 

 distance. Several grasses have similar wing-like bracts; 

 of these perhaps the Quaking Grass is the best known. 

 In the Hornbeam both the bract and two bracteoles are 

 used for a parachute. The Lime uses only one large flat 

 and very thin bract, which is attached to part of the 

 flower stalk ; from this hang the small nuts, at such an 

 angle that the wind must carry the fruit some distance 

 before it drops to the ground. The principle is that 

 utilised in kite-flying. 



In the following cases the elasticity of the stalk is of 

 great assistance to the wind in dispersal. The Cow Pars- 

 nip has two flat and thin wing-like half-fruits, hung from 

 the top of the fruit-stalk, which carries them. If the 

 whole inflorescence is bent over in the way in which it 

 would be carried by an animal passing, it springs back 

 as soon as it is set free and the fruits fly off. There- 

 upon they are caught by the wind, which, assisted by 

 the momentum due to the elastic springing back of 

 the stalk, may carry them a distance of six feet or 

 more from the parent plant. The very curious shape 

 of the fruit of Angelica, and the flattened character of 

 the Woad fruits {Cruciferae)^ show that they are dis- 

 persed in the same way. 



Many seeds also have curious membranous wings 

 around them. Thus, for example, Bignonia, various 

 Lilies, Honesty, and the Yellow-rattle, all have a thin 

 papery border round the seed. In the two last the 

 stalk of the inflorescence is very elastic. The wind is 

 sure to catch on the broad pods {silicuias) of the Honesty, 

 and the flat wide fruit of the Yellow-rattle ; and in a high 



