﻿TRUNK STRUCTURE. 



73 



in which only a part of peduncle bundle // appears, a complete peduncle-bundle 

 section is first to be seen in S. 246, wlieie the bundles of the subtending leaf base do 

 not closely approach. Beyond — that is, beneath the level of section 246 — owing to 

 the cutting of longitudinal section 249, only the right half of peduncle bundle // is 

 present. In section 247 the adjacent leaf-base bundles lie closer to the peduncle 

 trace, as also in the succeeding sections down to 25S, where the branch // b is 

 analogous to branch b of peduncle / in section 245. Note especially that in sec- 

 tions 216, 243-246 peduncle trace //is cut relatively more distal than is peduncle 



trace / in section 216. Below section 

 25S branch b of peduncle trace // tends 

 to split up and at the same time align 

 itself more concentrically; but its final 

 course has not been traced beneath 

 S. 261. Turning back to longitudinal 

 section 249, it may be determined that 

 the bundle supply of a subtending leaf 

 actually gives off a branch which passes 

 into peduncle //, a condition not found 

 in the case of leaf base L. Whether 

 there is an additional connection of // 

 with a lateral leaf base, the present 

 series of sections does not disclose. 



The general conclusion is that 

 the peduncular bundle is formed from 

 the union of several different bundle 

 strands in the lower part of its course 

 through the cortex, and that these 

 strands consist primarily of a main 

 branch arising directly from the woody 

 cylinder, which may, however, be con- 

 nected with either lateral or subtending 

 leaf traces. The leaf traces appear in 

 general to arise from the woody cylinder 

 as horseshoe bundles, with the phloem outside, these bundles soon assuming a more 

 or less brokenly-circular form in the most of their course through the cortex before 

 dividing up in the leaf base. 



The result obtained is to the writer an unexpected one, difficult to explain. 

 The apparent connection of the peduncle traces with leaf traces would seem to 

 indicate a renewal of growth activity of not only the woody zone of the trunk, but 

 possibly of the cortical traces, over all the lateral area of the trunk after the wilting 

 down of the leafy crowns of successive seasons. Of course, the order in which the 

 fruiting ineristeins arose in the peripheral cortex can as yet only be surmised from 

 the distribution of young fructifications of appreciable size. 



It is only fair to myself to call attention to the fact that the above series of sec- 

 tions was prepared when there was at my disposal only the rock-cutting machine 



39 C. — Medullary region, xylem, cambial hne, and pari 

 of the phloem of the peduncle bundle or woody cylinder. 

 Nearly continuous with 39 B. (X 100.) 



