570 



BOTANY 



rapa) (Fig. 580) is a plant of great economic importance. It is a biennial plant, and 

 in the first season forms a thick, swollen root bearing a bud consisting of a number 

 of thick -stalked, entire, succulent, and often crisped leaves. From this rosette of 

 leaves there springs in the second season a highly branched panicle, bearing the 

 inconspicuous greenish flowers. Ovary formed of three carpels. At the end of 



Fit;. 582. Agrostemma Githago. Flowering shoot and fruit (J nat. size). Poisonous. 



the first season the root contains cane-sugar as a reserve material, which at this 

 stage is extracted from the plant. By constant selection the percentage of sugar 

 is raised from 7-8% to an average of 14% ; it may, however, reach 21-26%. The 

 original form of the Sugar Beet is Beta patula. Cfienopodium and Atnplex are 

 common weeds near human dwellings. 



Family 3. Caryophyllaeeae. Annual or perennial herbs, very 



