226 TROPICAL NATURE, AND OTHER ESSAYS. 



many of these are specially though, imperfectly pro- 

 tected ; some by a prickly coat as in the chestnuts, or 

 by a nauseous covering as in the walnut; and the 

 reason why the protection is not carried further is 

 probably because it is not needed, these trees producing 

 such vast quantities of fruit, that however many are 

 eaten, more than enough are always left to produce 

 young plants. In the case of the attractively coloured 

 fruits, it is curious to observe how the seeds are always 

 of such a nature as to escape destruction when the 

 fruit itself is eaten. They are generally very small 

 and comparatively hard, as in the strawberry, goose- 

 berry, and fig ; if a little larger, as in the grape, they 

 are still harder and less eatable ; in the fruit of the 

 rose (or hip) they are disagreeably hairy ; in the orange 

 tribe excessively bitter. When the seeds are larger, 

 softer, and more eatable, they are protected by an 

 excessively hard and stony covering, as in the plum 

 and peach tribe ; or they are inclosed in a tough horny 

 core, as with crabs and apples. These last are much 

 eaten by swine, and are probably crushed and swallowed 

 without bruising the core or the seeds, which pass 

 through their bodies undigested. These fruits may also 

 be swallowed by some of the larger frugivorous birds ; 

 just as nutmegs are swallowed by pigeons for the sake 

 of the mace which incloses the nut, and which by its 

 brilliant red colour is an attraction as soon as the fruit 

 has split open, which it does upon the tree. 



There is, however, one curious case of an attractively 

 coloured seed which has no soft eatable covering. The 

 Ahrus precatoria, or ''rosary bean,^' is a leguminous 

 shrub or small tree growing in many tropical countries, 



