Terminal and Initial Parenchyma in Wood

Abstract

MR. K. A. CHOWDHURY'S remarks upon the position of the parenchyma in Terminalia tomentosa1 would seem to be applicable to other woods also. A recent examination of the wood of Cedrela odorata in this laboratory showed that the larger vessels of the early wood are partly embedded in parenchyma, some of which, judged by its position, was laid down rather earlier than these vessels. It is possible that the latest wood of a season's growth consists chiefly of parenchyma, and that the early wood of the following season is similarly constituted; but the parenchyma is sufficiently homogeneous to render this possibility improbable. Another specimen of Cedrela, probably C. odorata, showed that the parenchyma separated a region of rather small, fairly thick-walled fibres from another of larger, relatively thin-walled fibres; the comparatively large size and thin walls of the cells of the parenchyma in both these specimens suggest that it was laid down at the beginning of a season's growth, not at the end; it is desirable to confirm this by studies on the living tree.