Figure 11.3–Sinkers (A-F) and bark strands (E-F) of Arceuthobium americanum on Pinus contorta; in transverse section (A, D-F) or tangential sections (B-C). A: sinker (s) showing dilation at beginning of year’s growth; xylem-to-xylem contact at unlabeled arrow, x100. B-C: infected rays (ir) in host bark, x100. D: xylem (x) of parasite extending across host cambial zone (vc), x100. E: xylem leading to bark strand (b), x100. F: tiered arrangement of cells (t) in sinker portion embedded in host bark, x100.