EXERCISES WITH STEMS AND BUDS 43 



wedge-shaped fibro- vascular bundles separated by (c) the radiating 

 medullary rays and (d) the concentric circles or annual rings. 



0. The Parts in Large Timber. Examine the cut end of a large 

 stem or tree trunk and note the same points as in the preceding exercise. 

 Examine the enda of sawed timber and determine the above parts. Trace 

 them in the long section of the timber. 



7. Rise of Sap in Stems. Stand the freshly cut stems of Begonia, 

 horse-chestnut and other plants in water colored with eosin or red ink 

 for 30 minutes, one hour, and for 24 hours. Cut off small pieces, beginning 

 at the base and examine with a hand lens. Note the part through which 

 the colored fluid rises and the height to which it has risen. 



8. Persistent Upward Tendency of Stems. Take an upright, pot- 

 ted plant and place in a horizontal position (pot and all). Make a dia- 

 gram to denote the relative position of the parts and examine again at the 

 end of 24 and 48 hours. 



9. Dandelion Stem and Buds. Examine the short stem of the dan- 

 delion or similar plant. Count the number of buds you can find near the 

 surface of the soil. Does the number vary with the size and age of the 

 plant? Split the entire plant lengthwise and try to determine point of 

 union between stem and root. 



10. Examine the under-ground stem of Solomon's seal, May-apple, 

 Johnson grass or similar plants and compare with an aerial stem. 



11. Examine the bulbs of crocus, tulip, gladiolus, Indian turnip, 

 onion, etc., and note their general character. Cut them open lengthwise 

 and note the short stems and scale-like leaves. 



12. Examine a potato tuber and note its general character. Note the 

 arrangement of the eyes or buds. Compare with the fleshy root of a sweet 

 potato. Cut through it and note the fibro- vascular bundles just beneath 

 the epidermis or peeling. 



13. Buds of Twigs. Examine the stems of lilac, horse-chestnut, 

 hickory and maple. Note number, arrangement and relative sizes of the 

 buds on the different stems and on the same stem. 



14. Structure of Buds. Take the large buds of the lilac, horse- 

 chestnut, hickory, etc., and carefully dissect by successively removing the 

 scales and inner parts. Note the gradual transition from scales' to leaves. 

 Note the short, conical, undeveloped stem to which they are attached. 

 Compare the bud to a scaly bulb. (This study is most satisfactory if 

 conducted in the early spring when the buds are swollen. In winter the 

 stems should stand in water a few days before the study.) 



15. Opening of Buds. Cut a few of the newest and most vigorous 

 shoote from a lilac in winter or early in the spring before the buds open and 

 place in water in a warm room. Examine from day to day and note the 

 opening of the buds and growth of new shoots. 



