BIOLOGY OF HIGHER SEED PLANTS 7 



axis ? Have the lateral roots the same arrangement 

 as the leaves and branches ? Have they any definite 

 arrangement ? 



3. Bud structure, arrangement, and growth. 



a. Structure. How do the buds of an herbaceous plant, 



like the catnip, ragweed, or aster, differ from those of 

 a woody plant like the lilac ? Can you give reasons 

 for the differences observed, based upon the annual 

 and perennial habits of the two plants ? 



b. Arrangement and growth. Compare the buds of the 



herbaceous plant examined with those of the lilac as 

 regards arrangement and mode of growth. Is the form 

 of the plant you are examining determined by the 

 differences in the time and rate of growth of the ter- 

 minal and lateral buds ? For example, why are the 

 upper branches shorter than the lower ? Why is the 

 main axis longer than any of the branches ? How 

 explain the conical or rounded form of herbaceous 

 plants 011 the basis of bud growth? 



4. Light, air, and soil relations. What is the form of the 



entire plant under examination ? Are the leaves, flowers, 

 and seeds effectively displayed to sunlight and to air 

 currents ? Are the tips of the lateral absorbing roots 

 properly placed for absorbing water and soil salts ? 

 Consult Figs. 8 and 9 of the text. 



a. Construct an accurate outline drawing of the plant you 

 are studying, indicating the following points : 



(1) The form of the main central axis and the arrange- 



ment of lateral members. 



(2) The plan of the lateral branches, including the posi- 



tion of leaves, flowers, and fruits if present. 



(3) The general form of the entire plant and the display 



of absorbing leaf and root surfaces. 



