Fig. 7.1-7b. Magnification of vessel elements in fern (Pteridium). The three large cells at the bottom of the micrograph are vessel elements. The two arrows indicate the contact faces (it is possible to see that the “wall” between two cells is actually two walls and a middle lamella). Although this looks like an ordinary wall that you might see between two fibers, the paleness in each indicates that there is a scalariform opening there. The opening happens to be a perforation in this Pteridium, not a pit.