Fig. 7.2-5. Longitudinal section of club moss (Lycopodium). Fig. 7.2-3 shows that club moss has narrow tracheary elements with annular secondary walls; it also has narrow tracheids with scalariform pitting. Because the tracheids are so narrow, the scalariform pit apertures cannot be really wide, so these do not have the striking ladder-like appearance of the wide tracheids in Fig. 7.2-4.