82 VARIOUS MODES OF DISPERSION, [chap. 



Or let us take one natural order. That of the 

 Roses is particularly interesting. In the genus Geiim 

 the fruit is provided with hooks ; in Dryas it 

 terminates in a long feathered awn, like that of 

 Clematis. On the other hand, several genera have 

 edible fruits ; but it is curious that the part of a plant 

 which becomes fleshy, and thus tempting to animals 

 differs considerably in the different genera. In the 

 Blackberry, for instance, and in the Raspberry, the 

 carpels constitute the edible portion. When we eat a 

 Raspberry we strip them off and leave the receptacle 

 behind ; while in the Strawberry the receptacle con- 

 stitutes the edible portion ; the carpels are small, 

 hard, and closely surround the seeds. In these genera 

 the sepals are situated below the fruit. In the Rose 

 on the contrary, it is the peduncle that is swollen and 

 inverted, so as to form a hollow cup, in the interior of 

 which the carpels are situated. Here we must re- 

 member that the sepals are situated above, not below, 

 the fruit. Again, in the Pear and Apple, it is the 

 ovary which constitutes the edible part of the fruit, 

 and in which the pips are embedded. At first sight 

 the ffuit of the Mulberry — which, however, belongs to 

 a different family — closely resembles that of the 

 Blackberry. In the Mulberry, however, it is the 

 sepals which become fleshy and sweet. 



The next point is that seeds should find a spot 

 suitable for their growth. In most cases, the seed 

 lies on the ground, into which it then pushes its little 

 rootlet. In plants, however, which live on trees, the 

 case is not so simple, and we meet some curious 

 contrivances. Thus, the Mistletoe, as we all know, is 



