b BULLETIN OF THE NATURAL HISTORY SOCIETY. 



is very clear. One has only to recall the rapid spread and 

 great range of weeds, or the world-wide distribution of 

 many water-plants. Indeed, taken as a whole, it is pro- 

 bable that the aggregate locomotive accomplishments of 

 plants are fully equal to those of animals, even though 

 they are less rapid, less striking, less well-known. How 

 then, it is now our task to inquire, does it come to pass 

 that plants, themselves incapable of independent locomo- 

 tion, yet so perfectly secure it? The answer is in essence 

 this: It is secured to them by the separation of small •parts 

 of their substance capable of reproduction^ and the adjust- 

 ment on these of structures adapted to utilize the various 

 locomotive forces of nature. The end is thus as certainly 

 attained as among animals ; there is but a difference in 

 the method. Instead of the entire organisms moving,, 

 small reproductive parts move ; instead of by internal 

 powers it is by utilization of external agencies which 

 can move. 



Of the five needs for locomotion above-mentioned, the 

 third, fourth and fifth can be secured along with the first, 

 and indeed in the animal world all five are ensured by the 

 power of independent movement ; but among the higher 

 plants, the first and second require distinct methods. In 

 the first case, that of simple scattering to prevent over- 

 crowding, the problem is simply to remove to a consider- 

 able distance, and preferably to favorable situations, 

 reproductive parts of a plant ; in the second case, that 

 of effecting union of the sexes, i. e., union of pollen and 

 ovule, the problem is more difficult, for not only must 

 one of the uniting elements be removed to a distance, but 

 it IS to be deposited in a special position, i. c, the male is 

 not simply to be carried away from its producing struc- 

 ture, the anther, but it is to be deposited on a special part 

 of the female organ, the stigma, and the problem is made 



