18 



BOTANY 



tion 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 most rhizomes, on the other hand, the sympodial 

 nature of the axis can be easily distinguished ; as, for example, in the 

 rhizome of Polygonatum multiflorum (Fig. 21), in which, every year, the 

 terminal bud gives rise to an aerial shoot, while an axillary bud pro- 

 vides 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 gener- 

 ally terminates in a conical pro- 

 tuberance, designated the vege- 

 tative cone. As it is always 

 too small to be 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 un- 

 differentiated, it continues in em- 

 bryonic, condition, and it is from 

 the still embryonal vegetative 

 cone that the leaves take their 

 origin. They first appear in 

 acropetal succession as small, 

 ig. 17 -Apex of a shoot of a phanerogamic CO nical protuberances, and attain 



plant, v, Vegetative cone ; /, leaf rudiment ; , r . . „ > "" 



g, rudiment of an axillary bud. (x io.) a larger size the further removed 



they are from the apex of the 

 stem. As the leaves usually grow more rapidly than the stem which 

 produces them, they envelop the more rudimentary leaves, and over- 

 arching the vegetative cone, form, in this manner, a bud. Buds 

 are therefore merely undeveloped shoots. If they are to remain 

 for a long time undeveloped, as for example is the case with winter 

 buds, they are protected in a special manner during their period of 

 rest. 



Pig. 17.- 



