Brief Comments on the Nomenclature of Softwood Axial Resin Canals and Their Associated Cells

The terminology related to axial resin canals in conifers is briefly reviewed, standard terms are clarified and a new term is proposed. The definitions proposed are intended primarily for light microscopic observations. All the cells and spaces of an axial resin canal as differentiated from the axial tracheids are collectively referred to as the resin canal complex. The resin canal is the intercellular space itself, and the epithelium is the uniseriate layer of cells lining the canal. We propose the term subsidiary cells to include all cells exterior to the epithelium, which may be subsidiary parenchyma and /or strand tracheids.