184 LABORATORY AND FIELD EXERCISES 



(2) Summarize the similarities and differences of the 



inflorescence and flowers which you have observed 

 in comparing the dandelion with the yarrow. 



(3) Pollination, Proceed as directed under the labora- 



tory directions on the yarrow to find out the 

 mechanism of pollination in the dandelion. Com- 

 pare with the yarrow in this respect. Construct 

 figures for the dandelion similar to those of the 

 text on the yarrow. 



c. Fruit and seed. Study the fruit and seed of the dande- 

 lion and compare them with the fruit and seed of 

 the yarrow. 



(1) What special device has the fruit of the dandelion 



for dispersal ? What is the origin of the parachute 

 of hairs ? To what part of the flower do the 

 hairs correspond ? 



(2) Construct a series of three figures to illustrate the 



development of the fruit in the dandelion, begin- 

 ning with closed floral heads in which the flowers 

 have been recently fertilized. 



3. Seasonal history. Construct figures to illustrate the sea- 



sonal history of the dandelion. Is it annual, biennial, 

 or perennial ? By what means does it spread so rapidly 

 in lawns and along roadsides ? Study the relations of 

 its leaves to the grass beneath them. State five reasons 

 why the dandelion is so successful in gaining and 

 holding a place for itself in lawns. 



4. Analysis. Ascertain the species name of the dandelion 



by means of a manual. 



