P res err at ion of Species. 115 



their young to destructive agencies, were made pro- 

 lific to an amazing decree. In some of the lower 

 forms of animal life, where there is no care for the 

 young, the eggs are counted by millions. The 

 menu law is true of plants. Their seeds, 

 as a general thing, are food for animals, and are 

 exposed to destroying agencies, and their produc- 

 tiveness seems in proportion to the chances they 

 must run. Who can compute the thousands of 

 acorns that must have fallen from some of the old 

 oaks that count their centurie- of growth ? 



Among the pla; trivances 



for the distribution of their Seeds, that must be reck- 

 oned as one means of piv The 

 Impaticns opens its capsule with a sudden spring 

 which scatters the seed far from the parent stalk. 

 The cranesbill does the same, except that each seed 

 is held by its own little spring, which is ready to 

 throw its seed when ripe, like a stone from a sling. 

 Numerous seeds are edged with delicate membranes, 

 like the maple and elm, so that every gust of wind 



:ters them broadcast upon the earth. Others 

 still sail on silky balloons constructed with most 

 exquisite skill. One dandelion-seed would seem to 

 be enough to cut up all atheism by the roots. Its 

 finely spread balloon, with its seed hanging like a 

 miniature car as it floats through the air, is cer- 

 tainly a piece of mechanism perfect for the end in 



A -. The seeds of other plants are armed with 

 hooks, barbed like finest spears or hooks of steel. 

 Almost every person who has rambled in the fields 



