Few publications are available on Manihot anatomy. However, some on Euphorbiaceae could be reviewed. For example, applied wood anatomy to the systematics of Neowawraea phyllanthoides, a rare and endangered member of Euphorbiaceae endemic to the Hawaiian Islands. Its wood is diffuse-porous, perforation plates are simple, imperforate tracheary elements are thin-walled septate fiber-tracheids, rays are heterocellular and crystalliferous, and axial xylem parenchyma is restricted to a few scanty paratracheal and terminal cells.