XI THE SPECIAL COLOURS OF PLANTS 307 



forms the fruit of the strawberry ; while the mulberry, pine- 

 apple, and fig are examples of compound fruits formed in 

 various ways from a dense mass of flowers. 



In all cases the seeds themselves are protected from injury 

 by various device-s. They are small and hard in the straw- 

 berry, raspberry, currant, etc., and are readily swallowed 

 among the copious pulp. In the gTape they are hard and 

 bitter ; in the rose (hip) disagreeably hairy ; in the orange 

 tribe very bitter; and all these have a smooth, glutinous 

 exterior which facilitates their being swallowed. AVhen the 

 seeds are larger and are eatable, they are enclosed in an 

 excessively hard and thick covering, as in the various kinds 

 of "stone " fruit (plums, peaches, etc.), or in a very tough core, 

 as in the apple. In the nutmeg of the Eastern Archipelago 

 we have a curious adaptation to a single group of birds. The 

 fruit is yellow, somewhat like an oval peach, but firm and 

 hardly eatable. This splits open and shows the glossy 

 black covering of the seed or nutmeg, over which spreads 

 the bright scarlet arillus or "mace," an adventitious growth 

 of no use to the plant except to attract attention. Large 

 fruit pigeons pluck out this seed and swallow it entire 

 for the sake of the mace, while the large nutmeg passes 

 through their bodies and germinates ; and this has led to 

 the MTide distribution of wild nutmegs over New Guinea 



and the surrounding islands. 



In the restriction of bright coloiu- to those edible fruits the 

 eating of which is beneficial to the plant, we see the imdoubted 

 result of natural selection ; and this is the more e\'ident when 

 we find that the colour never appears till the fruit is ripe — 

 that is, till the seeds ^Wthin it are fully matured and in the 

 best state for germination. Some brilliantly coloured fruits 

 are poisonous, as in our bitter-sweet (Solanum dulcamara), 

 cuckoo-pint (Ai^um) and the West Indian manchineel. Many 

 of these are, no doubt, eaten by animals to whom they are 

 harmless ; and it has been suggested that even if some 

 animals are poisoned by them the plant is benefited, since it 

 not only gets dispersed, but finds, in the decaying body 

 of its ^dctim, a rich manure heap.^ The particular colours 

 of fruits are not, so far as we know, of any use to them other 

 ^ Grant Allen's Colour Sense, p. 113. 



