Plant tissues. Collenchyma.
Species: elderberry (Sambucus nigra).
Technique: paraffin embedding, section stained with Alcian blue / safranin.
Lamellar collenchyma shows primary cell thickenings in the internal and external tangential walls, both sides being parallel to the organ surface. Although it is mainly found in organs undergoing primary growth, in this picture, laminar collenchyma is located in an elderberry stem with secondary growth.