264 PLANT FAMILIES: DICOTYLEDONS. 



Materials. Leafy shoots, either fresh or pressed and dried. Flowers; 

 fresh as they appear in the spring ; if they cannot be studied immediately they 

 may be preserved in alcohol or in formalin. They are better fresh. 



Fruits, collected in the autumn and preserved riry. 



Omit the study of the horse chestnut, unless it is desired to 

 study it instead of the maple, since it belongs to the same order. 



424. The buckeye family (hippocastanaceae), The horse 

 chestnut (^Esculus hippocastanum) is largely planted in the 

 Northeastern United States as an ornamental tree. It is also 

 self-seeding in waste places. The family is represented in 

 other places by other species, the buckeye, from which the 

 family gets its common name, for example occurs in Ohio (the 

 Buckeye State). 



Exercise 75. 



425. The horse chestnut ( JEsculus hippocastanum). 



The leaves. Note the form and arrangement of the leaves. Sketch a leaf 

 to show its form and the parts. What kind of a leaf is it ? 



The inflorescence (mixed racemose). The flowers. What parts of the 

 flower are present? Is the flower complete or incomplete ; regular or irreg- 

 ular ; perfect or imperfect ? 



Describe the calyx ; the corolla ; describe a petal, its form and color. 

 How many petals present ? 



The stamen. How many present ? Sketch a stamen. 



The pistil. Describe the form of the pistil, its parts ; how many carpels 

 are represented in the pistil ? What is the character of the surface of the 

 ovary ? 



The mature fruit. What is the character of the surface of the mature 

 fruit ? Describe the form of the fruit. What parts of the flower are united 

 to form the fruit ? What is the difference between the fruit and a seed in the 

 horse chestnut? Examine the embryo in the seed ; note its large cotyledons 

 and the well developed hypocotyl. Why is the embryo not good for food for 

 man? 



Construct the floral diagram of the horse-chestnut flower. 



Material. Sprays of leaves and flowers, collected fresh. Mature fruits. 



