STEMS, BULBS AND BUDS 



41 



at the nodes of the stem. When the scales and leaves fall, there 

 remain well-defined scars, and since the basal part of the stem 

 elongates but very little as compared with the other parts, the 

 scars at the base are very close together (Fig. 9). Therefore, 

 the examination of these scars enables us to determine the annual 

 growth of the shoot. 



The arrangement of the buds on the shoot is subject to con- 

 siderable variation; in some cases they are alternate, while in 



I 



FIG. 19. The bulb type (a) tulip bulb; (6) same cut longitudinallyjtoi'showibasal stem and 

 . overlapping leaves. 



others they are opposite (Figs. 8 and 9). In most cases they 

 are borne in the axil or angle formed by the stem and leaf. Such 

 buds are known as axillary buds. Additional buds that are borne 

 above or to one side of the axil are accessory. The bud at the 

 tip of the stem is known as the terminal bud and usually makes 

 the most vigorous growth. Some plants produce two or more 

 terminal buds. Adventitious buds are borne on other parts of 

 the stems and in some cases on roots and leaves. Many buds 

 perish, while others make such a slow growth that they are over- 



