SEED-SCATTERING 279 



Some of the modes of scattering are peculiar and rare. 

 Thus the squirrel may forget some of his hidden stores 

 of beech-nuts, and germination may take place. There 

 is some evidence, too, that earthworms occasionally plant 

 trees. 



Sometimes the fruit or the seed has some peculiarity 

 which mechanically assists lodgment in the soil, some- 

 what in the same way as the corkscrew-like automatic 

 boring of the egg-case of the Port Jackson shark effects 

 fixation in a crevice in the rocks. A long bristle or awn 

 in the stork's-bill and some grasses begins to twist under the 

 influence of the moisture in the soil, and literally bores its 

 way in. And again, the wall of the seed or the fruit may 

 have a mucilaginous sheath, as in the case of quince and 

 flax, which effects attachment to the soil, and also serves 

 to absorb water like a sponge. But even more interesting 

 is the adaptation in the pea-nut (Arachis hypogcea), whose 

 fruit stalk curves down to the ground and pushes the 

 pod in, reminding one in a quaint way of some animal 

 hiding its egg in the ground. Not less effective is the 

 behaviour of the ivy-leaved Toad-Flax (Linaria cymballaria) , 

 which beautifies so many old walls. The fruit stalks 

 bend away from the light, which is learnedly called being 

 negatively heliotropic, and the result is that the capsules are 

 actually pressed into the crannies and crevices. A peculiar 

 idiosyncrasy has become the basis of an adaptation that 

 works extraordinarily well, as we may see in watching the 

 rapid spreading of this " Mother of Thousands," as the 

 plant is sometimes called, over a wall or a cliff which seemed 

 anything but a hospitable territory to colonise. 



Cases like pea-nut and toad-flax suggest an approxima- 

 tion to what one is tempted to call " parental care," were it 

 not that such irrelevancies of expression are apt to mislead. 

 But they are rare, and certainly far from typical. The big 



