|
|
|
|
|
Viburnum opulus L.
|
Water Elder
|
Caprifoliaceae
|
|
|
|
Transversal section |
|
|
|
Diffuse-porous. Relatively small pores, generally solitary. Indistinct growth ring boundaries, marked by 2 to 3 rows of radially flattened ground tissue cells at the end of latewood. Diffuse apotracheal parenchyma. Rays occasionally almost indistinct. |
|
|
|
Radial section |
|
|
|
Long scalariform perforation plates generally with more than 25 bars. Bordered pits in extremities often scalariform, in vessels from bordered pits to scalariform perforation plates, all transition forms present. Rays conspicuously heterogeneous, many rows of upright marginal cells. Fibre tracheids present. |
|
|
|
Tangential section |
|
|
|
Rays generally uni- to biseriate, rarely 3-seriate. Cells of uniseriate and sheath cells of multiseriate rays axially oval to rectangular, inner cells of multiseriate rays smaller. Average height of biseriate rays 8 to 15 cells. |
|
|
|
Key characters |
|
|
|
Diffuse-porous. Rays conspicuously heterogeneous. Long scalariform perforation plates with many bars. |
|
|
Remarks |
|
|
|
Viburnum opulus can be differentiated from Viburnum lantana by absence of spiral thickenings in the fibre-tracheids. |
|