108 



Mums explains readily, as Dr. J. E. Weiss ^) has pointed out 

 in the similar case of Tecoma radicn7is why the products of the 

 cambium in the pith have an inverted orientation, and the 

 phloem is given off toward the centre of the stem , while such 

 xylem elements as are produced at all arise from the outer 

 surface of the cambium. 



This connection between the outer and inner cambiums has 

 but small vertical extent, and on continuing the series of 

 cross-sections, it was found that the anomalous cambiums soon 

 detach themselves — if the expression may be allowed — from 

 the ends of the normal cambium, and the latter reunite 

 bridging over the openings left by the outgoing leaf- trace - 

 bundles. The series must however be followed considerably 

 farther before the typical structure of the internode is again 

 found, for the wood of each of the prominences becomes di- 

 vided into two parts by a bay of parenchymatic tissue (PI. XVIII 

 Fig 4 71, 7i) which increases rapidly in breadth. The parts of the 

 lobes, thus more and more widely separated from eachother, 

 unite in new pairs, /* with l\ P with /', PI. XVIII Fig. 4 , and 

 form two new lobes, the result being, that after the natural 

 irregularities produced by the insertion of the tendril and buds 

 have been passed , the stem has again its elliptical form but 

 the maximum diameter lies at right angles to that of the in- 

 ternode below. The parenchymatic bays {71, n) prove thus to 

 be the areas of soft wood („Holzausfullung") of the new inter- 

 node. The ring of first-formed secondary wood {r, r, PI. XVIII Figs 

 1 and 4) also undergoes a gradual alteration of form until in 

 like manner it regains its elliptical outline but with its maxi- 

 mum diameter at 90^ from its greatest dimension in the in- 

 ternode below. During this process the anomalous cambiums 

 suffer a corresponding change of position as represented in dia- 

 gram PI. XIX , Fig. 2 , where , at the side of the chief figure re- 

 presenting the longitudinal course of the anomalous phloem- 

 bundles , diagramatic cross-sections of the pith a, 6 , c etc. are 



1) 1. 



