112 SAGACITY AND MORALITY OF PLANTS. 



cousins, and to modify the free portion of their 

 calyx into a " clock " that the wind may waft their 

 fruits away. Singularly enough, another order of 

 plants far removed from both the above, the Valeri- 

 anacece have adopted a very similar contrivance, for 

 the same purpose. And one species, the Red Valerian 

 {CentrantJms riiber)^ abundant in most cottage gardens, 

 has even succeeded in developing a pretty and highly- 

 elaborate feathered pappus. 



The Cotton-plant (G'^j'.rj^////;/^) isnow clothing more 

 than half the human race with the long cellulose 

 hairs with which the surfaces of the seeds were 

 originally covered for the purpose of enabling the 

 wind to scatter them, just as we see it dispersing 

 the cotton-covered seeds of the Poplar, Cotton-grass 

 (Eriophoruni), and Sedges in our own country. 

 Here the end is gained by quite a different contriv- 

 ance to that adopted by the Dandelion and Thistle. 



Sometimes the services of the wind are enlisted 

 to convey seeds to a distance from the parent-plant, 

 not by ballooning, but on the screw-propeller principle. 

 This is illustrated by those peculiar kinds of fruits 

 called Samaras^ well known in the Maple, Ash, Elm, 

 and Birch. This type of mechanism is generally 

 borne by trees, and seldom by shrubs, and perhaps 

 never by herbaceous plants. For the greater height 

 of trees assists in the work, and when a samara is 

 detached the winged expansions are caught by the 

 wind, and revolved like the blades of a screw-pro- 



