50 STRUCTURE AND PHYSIOLOGY OF SEED PLANTS 



D. For comparison study at least one of the following kinds 

 of buds in their winter or early spring condition : hickory, 

 butternut, beech, ash, magnolia (or tulip tree), lilac, balm of 

 Gilead, cotton wood, cultivated cherry.^ 



Eeference. Ganong, 7. 



36. Study of a cabbage (a naked bud). Examine and sketch a 

 rather small, firm cabbage, preferably a red one, which has been 

 split lengthwise through the center, and note : 



A. The short, thick, conical stem. 



B. The crowded leaves which arise from the stem, the lower 

 and outer ones largest and most mature, the upper and inner- 

 most ones the smallest of the series. 



C. The axillary buds, found in the angles made by some leaves 

 with the stem. 



37. Study of vernation. Procure a considerable number of buds which are 

 just about to burst, and others which have begun to open. Cut each across 

 with a razor or very sharp scalpel ; examine first with a magnifying glass, 

 and then with the lowest power of the microscope. Make a careful sketch 

 of one section. Pick to pieces other buds of the same kinds under the 

 magnifying glass, and report upon the manner in which the leaves are 

 packed away. 



Reference. Kerner-Oliver, 2. 



38. The growing apex of the stem. The tip of the stem consists of tissue 

 which is undergoing (or in resting buds is ready to undergo) rapid cell divi- 

 sion, thus continuing the growth of the stem. The structure of this region 

 in dicotyledons is difficult to make out and it is not recommended that 

 beginners should undertake to study it. 



Hippuris.^ Choose a stem with a strong terminal bud, and trim away 

 from near the tip all the larger leaves. Cut off about a third of an inch of 

 the tip of the stem, hold it point downward between the thumb and fore- 

 finger, and try to get a smooth longitudinal section through the axis of the 

 bud. If the latter is first split into halves and then successive sections are 

 cut from each half, some one may be found to have passed exactly through 



1 If some of the buds are studied at home, pupils will have a better chance to 

 examine at leisure the unfolding process. 



2 If Hippuris is not available, Myriophyllum, which grows readily in aquaria 

 the year round, may be substituted. 



