Influence of the Adult Plant upon the Seedling. 327 
transverse section, are roughly the same as those of the parenchyma 
of the surrounding mesophyll; at lower levels, however, the size is 
Fig. 9. P. lanceolata. Transverse section of cotyledons, shewing one side 
of bundle. Mature and immature transfusion tracheides (/./.) are seen, x 355. 
more variable (Figures 5, 9, 10 and 11). The examination of longi 
tudinal sections shews a closer correspondence between the lengths 
of the transfusion tracheides and parenchyma: this is shewn in 
Figure 12. 
Fig. 10. P.lanceohita. Transverse section of a seed-leaf, shewing trans¬ 
fusion tracheides (t.t.) on the flanks and on the dorsal side of the bundle. 
X 200. 
As far as has been seen the thickening of the elements in 
question is either annular or spiral; in no case have bordered pits, 
which are characteristic of the transfusion tracheides of many Coni- 
ferae, been observed. It will, however, be remembered that there 
is much variation in this respect in the Gymnosperms ; although 
they are pitted in Pinus, they are annular or spiral in Podocarpus 
