Figure 11.2–Endophytic system of Arceuthobium americanum on Pinus contorta (A-C, E-F) and Phoradendron macrophyllum on Juglans hindsii (D); in transverse sections (A, C) or tangential section (B, D-F), through host bark (A-C) or wood (D-F). A: bark strand (b) with sinker (s), x100. B: bark strand to show tiered arrangment (t) of cells, x100. C: older bark strand showing secondary growth, x100: D: sinker; compare size to host rays (r), x40: E: infected ray showing host (h) and parasite (p) cells; pitting of axial and ray trachieds (rt) at unlabeled arrows, x250. F: infected (ir) and uninfected (ur) rays in xylem (x), x100.