438 THE POPULAR SCIENCE MONTHLY. 



boys, it probably despairs — it has acquired a comparatively hard and 

 woody shell, surrounded by a bitter and acrid husk. But its ally, the 

 bitter-nut, has hit accidentally upon a still more excellent and cunning 

 device : it has made the actual seed itself, the menaced kernel, a reser- 

 voir for its disagreeable bitter juice. Consequently, it needs much 

 less external protection than the hickory, and every American boy 

 knows well that its shell can be much more readily and easily broken 

 than that of its sweeter relations. Why hickory-nuts should be less 

 protected than butternuts, on the other hand, is a more difficult ques- 

 tion ; I incline to believe it is because of the greater number produced 

 by each tree annually, so that, in spite of all the havoc wrought by 

 squirrels and other depredators, enough must always have remained 

 and sprouted to keep up the full normal number of the species from 

 one generation to another. 



Almost all nuts follow more or less one of these two protective 

 types — the type of the hickory and the type of the bitter-nut — or even 

 sometimes both together. In the tropics, where forestine animals are 

 most developed, the nuts often reach a very high stage of evolu- 

 tion. The cocoanut is a familiar example : it has a soft outer husk, 

 stringy and loose, which breaks and deadens its fall from the tall and 

 graceful palm-trees on which it grows ; and inside this yielding, pro- 

 tective mat- work, it has a very solid shell, inclosing the large and rich- 

 ly-stored kernel. But the cashew-nut is, perhaps, the most remarkable 

 in some respects of any known example. It has taken most extraor- 

 dinary pains to preserve its kernel from injury ; and it has done so by 

 a curious combination of the tactics peculiar to attractive fruits with 

 those peculiar to repellent nuts. Its stalk swells out into a fleshy edible 

 tuber, something like a pear in shape, and endowed with all the usual 

 allurements of bright color and sweet taste. By this bribe, it entices 

 the South American monkeys to pick and aid in dispersing its seed. 

 But, at the same time, it carefully wraps up the nut itself in an acrid, 

 pungent covering, and places it at the outer end of the pear-like stalk. 

 Woe betide the adventurous monkey who tries to eat the inner kernel 

 of this decidedly well-protected nut ! The pungent juice of the rind 

 not only burns his tongue and lips, but even removes the skin from 

 his mischievous fingers as effectually as it could be removed by a can- 

 tharides-plaster. Hardly less quaint are the tactics adopted by the 

 familiar pea-nut of our childhood, which is really the underground 

 pod of a bean-like plant. This secretive vegetable has hit upon the 

 device of producing its seeds on subterranean branches, and so escap- 

 ing the notice of most open-air birds and mammals ; though, in thus 

 cunningly avoiding the Scylla of the upper earth, it has merely fallen 

 against the Charybdis of grubbing pigs and burrowing rodents. The lit- 

 tle English subterranean clover — I forget just now whether it grows in 

 America, too, and Dr. Asa Gray's magnificent work is not at hand — 

 has an even stranger plan for escaping from the sheep, on whose favor- 



