THE TRIBE OF THE ANGLE-WINGS 167 



plant I have in mind is the thistle, which from time im- 

 memorial has been one of the commonest neighbors of 

 man. It is found over the whole habitable globe, as well 

 as in many parts which are scarcely habitable. It has 

 many advantages in its struggle for life. The roots pene- 

 trate deeply into the soil; the thickened, spiny leaves are 

 so protected by their juices and their spines that they are 

 molested by very few enemies; the flower stalks are also 

 clothed in a similar armature; and the great heads of 

 flowers are surrounded with prickly involucres that gener- 

 ally prevent their being eaten by browsing animals or even 

 by phytophagous insects. The brightly colored blossoms 

 are abundantly provided with nectar and pollen, and they 

 attract great numbers of bees, moths, and butterflies, in 

 order to bring about cross-fertilization. But all of these 

 advantages are of little significance so far as wide dis- 

 tribution is concerned, compared with the feathery seeds 

 which are produced in such abundance and so generally 

 scattered by the slightest breath of wind that the word 

 thistle-down has come into general use to express a lightly 

 moving object. These airy seeds have been riding on the 

 wings of the wind all over the surface of the earth for un- 

 told millions of years. Doubtless during severe storms 

 they may be carried thousands of miles, and it is easy to 

 think that one of them might readily go half-way round 

 the world before it found a resting place. Wherever such 

 a seed alighted and found the condition of a moist soil and 

 slight protection, it would be likely soon to spring into 

 growth and to start anew the development of its ancient 

 race. 



The thistle, however, has not been entirely unmolested 

 during its aeons of existence. There has been developing 



