Helical thickenings and helical cavities in normal and compression woods of Taxus baccata

摘要: The longitudinal tracheids in compression wood of Taxus baccata contain helical thickenings but no cavities. are as frequent and well developed have the same ropelike appearance normal this species. They an integral part S3 S2 orientation innermost microfibrils these layers. Except for absence cavities presence thickenings, possess all anatomical features typical such cells, including a rounded outline, intercellular spaces, thick S1 layer, highly lignified (L) layer. Pronounced Pseudotsuga menziesii contains thickenings. Thickenings seem to be mutually exclusive Taxus.