11 



the same way as an animal would do when irritated by the 

 discomfort of having the appendages sticking in its fur. A great 

 number, estimated at about 10 per cent., of all flowering plants 

 distribute their seeds by this process. One plan is to have 

 attached to the seed either one or more bristles terminating 

 in a single or compound hook or claw. One of the most 

 beautiful examples of this is to be seen in the fruit of the 

 common bennet (Genm Urbamcm), which grows in every 

 ditch. 



Many other are the devices by which seeds attach them- 

 selves to animals, some are furnished with barbs, others with 

 prickles or spines, others with various sorts of glutinous gum. 

 The arrangement of all these hooks, spines, barbs, &c, is 

 almost infinite in variety, all, however, being used for the 

 same purpose, namely, that of dispersal. 



Many seeds are carried on the feet of animals and even 

 of birds. In trampling on damp and yielding ground, 

 numbers must be picked up with the moisture and dirt, and 

 so be carried from one place to another. 



But perhaps the most interesting and wonderful con- 

 trivances for dispersal are found when one comes to consider 

 the various mechanisms with which plants are supplied for 

 the throwing of their seeds. There is absolutely no limit to 

 the variety of inventions furnished for this purpose. In this 

 category we find slings, catapults, squirts, spring guns, and 

 artillery of all sorts. In all these cases the weight of the 

 projectile and the strength of the mechanism are determinate 

 factors which impose a limit on the distance thrown, and the 

 seed cannot travel beyond this limit unless some other 

 agency intervenes. It not infrequently happens, I apprehend, 

 that another agency takes up the work ; for example, when 

 the plant has done its best, birds and animals may step in 

 and still further carry on the dispersal. A well known 

 example of interesting ballistic appliance is to be seen in 

 the geranium or cranesbill family. [This and other devices 

 including that of the pea and balsam families were described.] 



Time would fail me to speak of a thousandth part of the 

 wonderful machines provided by Nature for the projection of 

 fruits to a requisite distance, the perfection of the machinery 

 is not to be surpassed ; the parts are, moreover, so placed as 

 to give the largest trajectory of the projectile. [Examples 

 to illustrate this were given.] 



