DISSEMINATION OF SEEDS 173 



151. Laboratory study of vegetative propagation. 



A. In moist earth or sand plant pieces of potato tubers, each 

 containing one or more " eyes," and others without eyes. 

 Note results and sketch any plants that are produced. 



B. Plant bulbs and bulblets of onion and note the compara- 

 tive growth of the plants produced. 



C. In sand which is kept moist plant cuttings of any of the 

 following plants : "geranium," Trao?esca7i^m, willow, cotton- 

 wood, currant, raspberry, blackberry, and grapevine. When 

 the cuttings have rooted, sketch some of them, and' decide 

 whether the roots spring indifferently from any part of 

 the stem. 



D. If obtainable, put some vigorous Bryophijlhim leaves on 

 moist sand, cover with a bell glass, and sketch the leaf with 

 young plants, if any appear. 



152. Field study of dissemination of seeds. 



A. Examine the region about any tree or shrub which has no near 

 neighbors of its own kind, and try to trace tlie distance to which its 

 seeds have been carried. In case enoiigli seedlings are found to war- 

 rant it, make a map to show their distribution with reference to the 

 parent tree. 



B. Discuss the means by which the seeds have been carried. 



C. Watch such trees as elms, maples, lindens, willows, sycamores, and 

 cottonwoods, when the fruits or seeds are fully ripe, and find out how 

 far they travel. What trees hold many of their seeds after they are 

 fully ripe ? What are the advantages of this ? 



D. Look for as many contrivances for seed dispersal as possible, ami 

 classify the plants studied into those with fruits or seeds dispersed : 



(1) by wind. 



(2) by water. 



(3) by animals. 



(4) by some contrivance for shooting or slinging the seeds. 



Referenck. Kerner-Oliver, 2. 



153. Laboratory study of dissemination of seeds. 



A. Find out which of the wind-carried fruits and seeds fall 

 most slowly from the laboratory ceiling to the floor. 



