382 The Living Plant 



call turf. Our native ferns, as well, have stems that creep, and 

 send up the beautiful fronds from new soil. There are other 

 plants, like Solomon's Seal, which grow onward under ground 

 year after year, the old parts dying behind as the new are devel- 

 oped in front; and such plants may wander a considerable dis- 

 tance through the woods, carrying their new branches ever into 

 new ground. In the tropical forests there are epiphytes which 

 wander in this manner over tree trunks, and certain undergrowth 

 kinds which grow forward a little on stilt-like aerial roots. 



Fio. 148. Fairy Rings, of Mushrooms, originating as explained in the text. Three com- 

 plete rings and a partial one appear in the picture. (Reduced from Kerner's Pflan- 

 zenleben.) 



Roots possess a certain power of shortening their length during 

 later growth, and advantage thereof is taken by some bulbous 

 plants, like the Tulips. New bulblets are formed in the axils of 

 the scales of the old ones, and then are pulled an appreciable dis- 

 tance from the parent by the shortening of their own radiating 

 roots after these have become fixed in the soil. And there are 

 other minor ways in which growth helps to spread plants, though 

 I think the aforementioned include all of real consequence. 



