COMPAKISONS OF SYSTEMS AND TYPES OF BRANCHES. 51 



selves with a few general temis that will enable us to indicate more 

 directly the nature of these various kinds of branches. A primary- 

 distinction can be made as to whether a bud is laid down when the 

 branch grows or is formed afterwards from unspecialized tissues of 

 the bark. Buds that are not adventitious in the latter sense, but are 

 formed with the growth of the internode to which they belong, might 

 be called natal buds. 



xVdventitious branches are not supposed to have regularitj^ of posi- 

 tion, but such regularitjr should not be allowed to obscure their ad- 

 ventitious character if they are formed subsequent to the growth of 

 the internode. The loss of the original axillary bud may be followed 

 by the development of an adventitious axillary bud, as happens in 

 coffee. Also the flower buds of coffee appear to be adventitious to a 

 very considerable extent, and perhaps altogether so. With severe 

 pruning, leafy branches may also be forced from the axils of the 

 kaves of the fruiting branches long after the normal production of 

 flowers and fruits would have ceased. This may be taken to show 

 either that additional adventitious buds can be formed in the axils 

 after the fruiting period is past, or that the axillary buds of the 

 fruiting branches have previously remained dormant and not taken 

 part in the jDroduction of flowers and fruit. 



The fact that flower buds can be adventitious only emphasizes the 

 more the absence of any general connection between origins, positions, 

 and functions, for plants have always had flowers, or at least the 

 essential sexual organs, even before they had the jjresent specializations 

 of their vegetative parts into branches and leaves. Flower buds could 

 never be considered adventitious if we were to attach any functional 

 sense to the term, but they appear adventitious with respect to the 

 time and method of origin on the individual jalant. 



The terms axillary and extra-axillary are sufficient, perhaps, for 

 the designation of the positions of the two kinds of buds on any par- 

 ticular plant, but as a general term extra-axillarj'' is extremely in- 

 definite. It groups together buds arising from internodes of the stem 

 or trunk and those coming from the roots, as in the plum, pear, bread- 

 fruit, and sweet potato. It does not distinguish between the condi- 

 tions to be found in coffee, where the extra-axillary branch is far 

 above the axil, and in cotton and Castilla, where the extra-axillary 

 branch is at the side of the axil. 



Some might prefer to describe the cotton j^lant or the coffee tree as 

 having two axillary buds, and thus avoid the tendency to confuse 

 extra-axilhiry position wath adventitious origin, but it is evident that 

 no scientific object can be gained by applying the same name to things 

 as different as the two kinds of branches. In the strictly mathe- 



198 



