18 BOTANY PART I 



appearance quite different from its typical form. The more vigorous 

 branches may then, apparently, form a main axis, from which the 

 weaker branches seem to spring, just as if they were lateral branches. 

 This mode of branching (Fig. 16 Ab} is illustrated by the Selaginellas. 

 Such an apparent main axis (s, s) is termed, in accordance with its 

 origin, a SYMPODIUM. On the other hand, in the monopodial system 

 two or even several lateral branches may develop more strongly than 

 the main axis, and so simulate true DICHOTOMY or POLYTOMY. Such 

 monopodial forms of branching are referred to as FALSE DICHOTOMY 

 (Fig. 16 Ea) or FALSE POLYTOMY, as the case may be. A good 

 example of false dichotomy may be seen in the Mistletoe (Viscum 

 itHniin). If, however, a lateral branch so exceeds the main axis in 

 development pushing the apex of the latter to one side, that it seems 

 ultimately to become a prolongation of the axis itself, a sympodium is 

 again formed (Fig. 16 Eh). This is what occurs in many of our forest 

 trees, e.g. the Lime and Beech ; in both of these trees the terminal buds 

 of each year's growth die, and the prolongation of the stem, in the 

 following spring, is continued by a strong lateral bud, so that in a 

 short time its sympodial origin is no longer recognisable. In many 

 rhizomes, on the other hand, the sympodial nature of the axis can be 

 .easily distinguished ; as, for example, in the rhizome of Polygonatum 

 multiftorum (Fig. 23), in which, every year, the terminal bud gives 

 rise to an aerial shoot, while an axillary bud provides for the 

 continuance of the axis of the rhizome. In the flower-producing 

 shoots or inflorescences of Phanerogams the different systems of 

 branching assume very numerous forms. These will be more fully 

 described in their proper place. To such inflorescences belong the 

 ventrally coiled dorsiventral shoots which produce new shoots from 

 their convex dorsal surfaces, instead of in their leaf -axils. 



The Shoot 



The Development of the Shoot. Under the term shoot a stem 

 and its leaves are collectively included. A stem possesses an apical 

 mode of growth (Fig. 17), and its unprotected growing point is 

 described as naked, in contrast to that of the root with its sheathing 

 root-cap. The apex of the shoot generally terminates in a conical 

 protuberance, called the VEGETATIVE CONE. As it is usually too 

 small to be clearly visible to the unaided eye, it is best seen in magnified 

 median longitudinal sections. So long as the apex of the shoot is 

 still internally undifferentiated, it continues in the embryonic con- 

 dition, and it is from the still embryonal vegetative cone that the 

 leaves take their origin. They first appear in acropetal succession 

 as small, conical protuberances, and attain a larger size the farther 

 removed they are from the apex of the stem. As the leaves usually 

 grow more rapidly than the stem which produces them, they envelop 



