?78 PHYSIOLOGICAL BOTANY. PART II. 



dispersion ; but as nature has destined these fruits to 

 be the favourite food of many birds and other animals, 

 they become instrumental in doing this. Animals after 

 swallowing these fruits digest the pulp only, whilst the 

 seed is voided by them in a state better fitted for ger- 

 mination than it was before. 



(278.) In capsuliir Fruits. Under this denomina- 

 tion may be included all fruits whose pericarp consists 

 of a dry cover, which generally becomes detached from 

 the seed, and bursts regularly along a line of suture, 

 separating it into distinct valves. Most of these fruits 

 are many-seeded, and their dispersion is commonly 

 effected by the agitation of the wind, which shakes a 

 few at a time from the capsule. In some cases they 

 are so arranged that their dispersion is necessarily 

 protracted, whilst in others it is speedily accomplished. 

 Some fruits retain their seed long after they are ripe, 

 as though it were necessary they should be thoroughly 

 dried. Some capsular fruits project their seeds to a 

 distance, by the elastic force with which their valves 

 suddenly burst when thoroughly ripe. The Balsams 

 (Iwjxitieiis) are a familiar instance of this, in which 

 the effect is acceleraled or suddenly stimulated by the 

 slightest contact of the. finger. The genus O.ralis has 

 the seeds covered with an elastic arillus, which sud- 

 denly bursts after the capsules have opened, and turning 

 the inside outwards projects the seed to a considerable 

 distance. 



(279-) Peculiar Modes of Dissemination. The 

 ordinary effect produced by moisture upon the valves of 

 a seed-vessel is to keep them closed ; but there are 

 some remarkable exceptions to this law. In the Ona- 

 yrarife, which grow naturally in moist places, the valves 

 open in moist weather, and the seeds are then scattered. 

 There is a small annual cruciferous plant, called the 

 Rose of Jericho (Anastatica hierochuntina), which 

 grows In the driest des'erts. When the seeds are ripe 

 the plant withers and the branches coil together, so 

 that the whole mass forms a sort of ball. As the root 



