SUMMARY OF SEEDLINGS 111 



Summary of Seedlings. — Seedlings of Flowering Plants are 

 either nionocotyledonous or dicotyledonous on the basis of the 

 number of cotyledons. Among the Monocotyledons the tem- 

 porary root system is a prominent feature, and the cotjdedon may 

 remain in the ground as in the Grasses or be raised to the light as 

 in the Onion. In Dicotyledons the first root system is usually 

 the permanent one and may consist mainly of a tap-root or of 

 many roots nearly equal in size. In many Dicotyledons the coty- 

 ledons are raised to the light where they function to some extent 

 like ordinary leaves. The fleshy ones, however, lose their stored 

 food in a short time and fall from the plant. In some cases, as 

 the seedhngs of Buckwheat, Morning Glory, and Cotton illustrate, 

 the cotyledons become more leaf -like and persist longer, although 

 they are always easily distinguished from true leaves. In some 

 Dicotyledons the cotyledons remain in the soil and the plumule is 

 raised to the light by the elongation of the stem of the epicotyl. 



