Fig. 16.2-2. Transverse section of bark of ash (Fraxinus). Secondary phloem of ash also has alternating bands of conducting cells (lightly stained here) and fibers (darkly stained). The arrows on the left indicate some of the many narrow rays; notice that one ray is greatly enlarged (upper arrow). Also, the axial bands of sieve tube members and fibers are distorted near the top of the micrograph: cell division and enlargement of at least some of the parenchyma cells has pushed the axial masses apart.