Fig. 3.

Structure of elements of Douglas fir wood formed in stump before the tree was cut (a) and in the stump’s overgrown tissues (b−k). a Macerated axial tracheids in normal wood of straight shape. b Macerated tracheary elements of the overgrown, different shapes. c Short tracheary elements formed a spiral-like arrangements around parenchymatous cells (arrow) located in the tracheid concave region. d Bent end of tracheary element with the parenchyma cells (arrow) located in the concave side. e Circular (red line) arrangement of tracheary elements around xylem ray-like parenchyma cells (blue line). f Rounded shape of tracheary elements (red line) near the xylem ray-like structure. g−h Examples of various shape of tracheary elements in overgrown tissue: circular g, furcated h, bent with local concave (arrow) region (i), with two very short lateral tips (arrow) in central cell region j, with curved end k. Scale bars = 200 μm (a, b), 50 μm (c, g−k), 40 μm (d), 100 μm (e, f)