Fig. 15.2-2. Tangential section of wood of white pine (Pinus strobus). In this view, imagine that we have peeled the bark off the tree and are now looking toward the center of the trunk–if the wood were transparent, we would be able to see all the way to the pith. As in all conifers, most rays here (some are indicated arrows) are uniseriate and vary from being only two cells tall to many cells tall (lower right corner). The center ray is wider than the others because it has a resin canal running through it. Because this is a tangential section, the rays are running directly away from us, back into the screen. The resin canal here would be running toward the pith. All the vertical, elongate cells are tracheids of the axial system.
This high magnification view shows the many ordinary ray cells (all parenchyma cells) and the larger epithelium cells of the resin canal.