STUDIES OF SEED-PLANTS 225 



of mud on the feet of wading birds, and nuts buried or hidden 

 away by birds or squirrels and then never eaten. 



Students of botany should guard against the common 

 tendency to look upon adaptations for dispersal of seeds as 

 having developed because plants required them. That this 

 is not true is indicated by the fact that numerous species of 

 plants have no obvious special methods for distributing seeds. 

 All that we are justified in stating is that plants with seeds 

 specially adapted for dissemination have a better chance of 

 spreading over a large territory. We do not know why or 

 how plants acquired their peculiar methods of seed-dispersal. 



SEED-PLANTS REPRODUCING WITHOUT FLOWERS 

 AND SEEDS 



218. While the flowering plants naturally reproduce from 

 seeds, many of them may also reproduce by other methods. 

 Many cultivated plants are examples. Strawberry plants are 

 commonly obtained from branches (called runners) which 

 creep over the ground and take root at the joints or nodes, 

 and form new plants at these points. In this way one plant 

 has formed more than fifty new plants in a single summer. 

 Black raspberry bushes and grape-vines bend over, form 

 roots, and develop new plants where they touch the ground. 

 Red raspberry bushes multiply by forming young plants 

 from underground branches resembling roots. New plants 

 start from roots of osage-orange and some other trees. Some 

 flowering plants may reproduce from leaves; the best ex- 

 ample is the " sprout-leaf " or bryophyllum, a garden plant 

 whose leaves fall to the ground, form roots and shoots at the 

 notches on edges of the leaves, and thus each leaf may form 

 a number of new plants. Some begonia leaves will propagate 

 in the same way. Still other flowering plants propagate 

 from bulbs (which are short stems with leaves). This is well 

 illustrated by certain kinds or varieties of onions. The com- 

 mon onions (" seed onions ") are grown from seed in one 

 Q 



