Fruits and Seeds. 203 



They would occur, for instance, among trees and 

 on water-plants. On the other hand, if they are 

 developed that they might adhere to the skin of 

 quadrupeds, then, having reference to the habits 

 and size of our British quadrupeds, it would be no 

 advantage for a tree or for a water-plant to bear 

 hooked seeds. Now, what are the facts ? There 

 are about thirty English species in which the dis- 

 persion of the seeds is effected by means of hooks, 

 but not one of these is aquatic, nor is one of them 

 more than four feet high. Nay, I might carry the 

 argument further. We have a number of minute 

 plants which lie below the level at which seeds 

 would be likely to be entangled in fur. Now, none 

 of these, again, have hooked seeds or fruits. It 

 would seem that, in the history of the earth also, 

 the appearance of the families of plants in which 

 the fruits or seeds are provided with hooks coin- 

 cided with that of the land quadrupeds. 



5. Again, let us look at it from another point of 

 view. Let us take our common forest trees, shrubs, 

 and tall climbing plants ; not, of course, a natural 

 or botanical group, for they belong to a number 

 of different families, but a group characterised by 

 attaining to a height of, say, over 8 feet We will 

 in some cases only count genera ; that is to say, 

 we will count all the willows, for instance, as one. 

 These trees and shrubs are plants with which you 

 are all familiar, and in this country are about 33 in 

 number. Now, of these 33 no less than 18 have 



