200 ANTHOTAXY 



extension is impossible, except by the rare and abnormal process of 

 Proliferation. Inflorescences so limited are called Determinate or 

 Definite. 



Vertical Extension by the Branches. — Although vertical extension of 

 the original stem of a determinate inflorescence is not possible, it can 

 take place through the branches, the same as in other sympodia. The 

 effects of such development are the same as in other forms of sympodial 

 growth in which there is a transformation of the apex of the original 

 stem — as, for instance, in our explanation of such a mode of develop- 

 ment of the tendril (Fig. 431). To apply this principle in the case of an 

 inflorescence, we have only to assume a flower developed at the tip of 

 every branch in Figs. 433 to 435. Flower a would develop first; b, 

 although the second in order, and hence a branch, and afterward c, 

 would be more elevated, and would thus seem to prolong the vertical 

 extension of the stem. The development being successively by nodes 

 whose original points of origin were successively lower than that of the 

 terminal flower, is structurally and really Descending or Basipetal, 

 even though by the upward growth of the successive branches they be 

 at successively higher levels, the order apparently in the opposite 

 direction. By the development at each node of a pair of opposite 

 branches we get the apparent bifurcating or dichotomous form (Fig. 

 435). If but one branch grow from a node, and these successively from 

 right to left, the zig-zag or Flexuose form of rachis is produced (Fig. 

 433), and if constantly from the same side, or apparently so, the Cir- 

 cinate (Fig. 434). 



The descending or basipetal nature of the definite inflorescence is 

 clearly shown when the successive branches remain short, each succes- 

 sively developed flower remaining at a lower level than that which 

 preceded it (Fig. 581). 



The Centrifugal Form. — Instead, however, of assuming either of these 

 two states, in which the flowers remain at different le\els, the branches 

 may radiate and elongate to different degress, ceasing their elongation 

 when their flowers have been brought to a uniform height, so that a 

 more or less flat-topped inflorescence results, the order of development 

 being from the center outward, or Centrifugal, as in the branches of 

 Fig. 584. 



Cymose Inflorescences. — This form represents the true Cyme, and 

 because of their relationship to it this entire series of inflorescences is 

 often denominated the Cymose. It will thus be seen that in different 

 forms of the cymose inflorescence, we may have the flowers all brought 



