10 



ELEMENTS OF UOTANY. 



plant woulfl assume a rogular, symmetrioal shape. But practically tho 

 vast iniijority oi' kucL i)lants arc unsyuiiiietricai, iiiairly because the ter" 

 minal bud — that is, tlie bud terminating^ tho main stem — is so much more 

 vigorous than the others, that having the start in the beginning it keeps 

 it and leaves the branches with comparatively little nourishment. In many 

 plants tho growth of tlie terminal bud is so vigorous that the axillarj' buds 

 never unfold and the stem remains always simple — that is, not branched. 



But suppose some accident destroys the terminal bud : then the ax- 

 illary buds, especially those nearest the seat of the injiu'y, are quickened 

 into activity, and a plant whose atem is naturally simple becomes branched. 



Fio. 15. — Solomon'h-sonl — n subterrnncan Btem [rhinome). Lraf parallel-veined. 



Again, some plants in germination ^have not one or two seed-leaves 

 only, but a cluster of them ; in these the branches normally assume aver- 

 ticillate character. Tliis is the rule in the pine f;)n!ily {(Jonifcnr). Others 

 still which start with their leaves in pairs, at a later stage produce them 

 alternatel}' ; here the branches are also alternate. And some plants have 

 forking branches, the growing Inxd ceasing activity at a certain point and a 

 pair of forking branches starting from the axils of the last developed leaves. 



This brief view of the growth of the stem and branches demonstrates 

 sufficiently that every plant in its development obeys a fixed law of its 

 being. Yet from a few primary forms arises endless divei ty ! 



Many of the forms of stems have received distinctive names, which are 

 made use of in botanical descriptions, as simple, not branched ; erect, 

 growing straight up; ascending, arishig oblic^uely ; twining, climbing 



