2o8 Introduction to Botany. 



occurrence, are the cocklebur, burdock, black snakeroot, 

 common beggar ticks, etc. 



137. Make drawings of seeds orfruits which are adapted 

 to being carried about by the wind. Good examples are 

 dandehon, maple, elm, milkweed, dogbane, pine, golden- 

 rod, and feathergrass. 



138. Make drawings and notes showing the method of 

 dispersion of the seeds of some water plants, such as 

 those of pond hlies. 



139. In your notes discuss, briefly the following ques- 

 tions : Of what advantage to the species is it for plants to 

 produce edible fruits .■" Would the minute ripened pistils 

 of the strawberry, or the small seeds of the fig, grape, 

 gooseberry, etc., be apt to be broken when the seeds are 

 eaten ? Of what advantage is the bitter taste of the seeds 

 of the orange ? What common plants probably have their 

 seeds scattered by birds .-' 



140. Determine the morphology of 'the various devices 

 for dissemination in the fruits and seeds studied, and record 

 observations and conclusions in your notes. 



141. Count the number of seedlings which spring up 

 in one square foot of ground, and as they grow older 

 note how many of them succumb in the competition for 

 food and light. 



DISCUSSION. 



143. Importance of Seed Dispersion. — A moment's re- 

 flection will convince the student that the dispersion of the 

 seed to some distance from the parent plant is of vital im- 

 portance to the continuance and well-being of the species. 

 If the seeds were to fall immediately beneath the plant, a 

 crowd of offspring would result, growing so close together 

 as to deprive each other of a sufficient amount of sunlight 



