8o HOOKED SEEDS ON BUSHES. [CHAP. 



adhere to the skin of quadrupeds, then, having 

 reference to the habits and size of our British 

 mammals, 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 dispersion 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 thing 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 also 

 seem, as Hildebrand has suggested, that in point of 

 time, also, the appearance of the families of plants in 

 which the fruits or seeds are provided with hooks 

 coincided with that of the land Mammalia. 



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 orders, 

 but a group characterised by attaining to a height 

 of say over eight feet. We will in some cases only 

 count genera ; that is to say, we will count all the wil- 

 lows, for instance, as one. These trees and shrubs are 

 plants with which we are all familiar, and are about 

 thirty-three in number. Now, of these thirty-three 

 no less than eighteen have edible fruits or seeds, such 

 as the Plum, Apple, Arbutus, Holly, Hazel, Beech, 

 and Rose. Three have seeds which are provided with 

 feathery hairs ; and all the rest, namely, the Lime, 

 Maple, Ash, Sycamore, Elm, Hop, Birch, Hornbeam, 

 Pine, and Fir are provided with a wing. Moreover, 

 as will be seen by the following table, the lower trees 



