2 ESSENTIALS OF BOTANY 



parts or organs — roots, stems, and leaves — which make up the main 

 bulk of what is known as the plant body. 



Draw the plant body considerably reduced. 



B. Roots. Note the origin and connections of the roots and state 

 some of the main differences between roots and stems of this plant. 



C. Stem. Select a portion of the stem with at least two well- 

 grown leaves attached, and draw (reduced), showing how the leaf- 

 stalks are attached. Describe how the stem branches. Cut off a bit 

 and see whether it is solid or hollow. Split ;^ small portion of it 

 through the center and see if the stem appears to be of the same 

 structure throughout and whether there is any bark or skin (epidermis) 

 covering the exterior. 



£>. Leaves. Draw one of the largest leaves (reduced) and one or 

 two of the smallest leaves (natural size). Include in the drawing 

 the leaf-stalks. Describe how the leaf -stalk is attached to the expanded 

 portion or blade of the leaf. Note where the principal veins originate 

 and what course they take through the leaf-blade. Describe the 

 principal differences between the upper and the under surface of 

 the blade. If growing plants are at hand, try to make out how the 

 tall kind of nasturtium climbs, that is, by what means it attaches 

 itself to any convenient support. Study plants growing undisturbed 

 and see whether the leaves are arranged at any definite angle with 

 reference to the sun's rays (Plate IV). 



The vegetative organs of the plant body, that is, the 

 parts which it uses in the processes of life and growth, 

 are the roots, stems, and leaves. Their functions are dis- 

 cussed in detail in special chapters, but here it may be 

 stated that the roots serve to fasten the plant to the earth 

 and to absorb from the soil water and dissolved materials 

 useful in the nutrition of the plant; that the stem con- 

 ducts water and plant foods and supports the leaves in 

 a suitable position to do their work; and that the leaves 

 perform most of the work of making plant food from the 

 raw materials (which are derived from the air and the soil), 

 and of respiration. 



