206 STATE HORTICULTURAL SOCIETY. 



But we find the methods of dissemination almost as varied as the 

 tind of seeds. In general, the methods of dissemination may be 

 grouped under three heads : 



First — Those that have some external, appendage or secretions 

 that facilitate transportation. We find good illustrations of this in the 

 external appendages of the one-seeded indehiscent dry fruits. Here 

 the whole fruit is carried by some external growth, as the single samara 

 of the white ash, the marginal wing of the birch and elm, the double 

 samara of the red maple. Sometimes the appendage is the remnant of 

 the style modified into a long feathery tail, as in the geum. Similar to 

 this is the papus of the dandelion. Functionally identical with these 

 are the wing of the pine seed, the tuft-like coma of the milk- weed, the 

 only difference being that in the latter case the appendage is an out- 

 growth of the testa of the seed. 



It may be that the seed is furnished with a gummy secretion that 

 causes them to adhere to an object coming into contact with them. 



Or, finally, the seed or seed-vessel may be covered with spines or 

 hooks that attach themselves to whatever touches them. 



Second — Those that have some internal mechanism that forcibly 

 expels the seed. Very striking examples of this can be seen in the 

 elastic springs in the ovaries of geranium aud touch-me-nots. 



Third — Those that have some attraction in taste, color and odor, 

 and become the food of birds, etc. 



We have noticed those thiugs in the structure of the seed that 

 favor dissemination ; let us now for a moment notice the agents that 

 accomplish it. We might briefly summarize by saying the wind, water 

 and animals. But it is accomplished in so many ways, direct and indi- 

 rect, that it will be interesting to mention some of them. It is easy to 

 see how the wind can carry seeds provided with wings and tufts, but 

 its action does not stop here. Light seeds of all kinds are carried by 

 ordinary winds, while gales, hurricanes and whirlwinds carry even 

 heavy seeds hundreds of miles from their habitat. E-ain falling beats 

 *out the seed from the pod and carries them off in the rivulets ; from 

 thence the route to the river and the deposit on the flood grounds is 

 but an easy sequence. 



Ocean currents bring seeds and even plants from foreign lands, 

 and, last of all, glaciers, which are no n.ean agents of dissemination. 

 But wind and water do not, by any means, do all the work. The part 

 animals play in this is marvelous. 



We will only take time to mention a few of the most characteristic 

 of these.. Many seeds and seeded fruits are the food of both man and 

 the lower animals. A vast majority of these seeds are untouched by 



