AN OUTLINE OF PHYTOBIOLOOY. 13- 



3. Slender stems or branches bend over and take root and 

 produce a new plant at their tips forming " stolons;" such are 

 some species of Rubus. 



4. Plants in which the main stem creeps horizontally either 

 above or below ground and in which the old parts die behind as 

 the new advance, attain locomotion by the very act of growth. 

 Ferns and Solomon's Seal are examples. Such plants may 

 branch and after a time by the death of the old connecting parts 

 may give rise to several independent individuals. In the tropics 

 there are epiphytic plants which creep along the stems of trees 

 and have this same habit, such as Pothot^. 



5. Bulbs may be drawn away from theii' producing plants 

 by the shortening of lateral roots. Many bulb plants which 

 form small side bulbs, send out from them, horizontally, slender 

 roots. Later, the connection of l)ulb with the old plant is 

 severed, the roots shorten and draw away bulb from plant. 

 Ornithoyahim nutans and Ttdipa sylvestris are examples. 



6. An inclined stem may develop aerial roots called " stilt 

 roots," by which it is nourished and supported several feet from 

 the ground : in time the old stem and roots die behind and the 

 plant continuing to grow and to' produce new roots, the plant thus 

 secures movement from place to place. None of our plants do' 

 this but it occurs in many of those of the tropics. A 

 modification of this habit, in that the old parts continue to grow, 

 there is profuse bi^anching, and the roots thicken up to stems,, 

 gives us the habit of the banyan. 



In addition to the formation of new plants at the ends 

 of laterally extended parts, many forms of separable 

 buds, bulblets, branches, etc., are formed directly 

 upon the plant, but these all are adapted to being- 

 scattered by some of the moving agencies, wind, water,, 

 etc., and they will be considered under those topics. 



