Fig. 5.3-14. Maceration of wood of box-elder (Acer negundo). The middle lamella can be dissolved by treating tissue with Jeffrey’s solution (a mixture of nitric and chromic acid – 10% each in water) at 60C for 18 to 24 hours (the acids do not damage either primary or secondary walls). This fiber is from box-elder wood, showing the long, tapered form of fibers. This is a libriform, xylary fiber. This magnification is too low to be able to see the small pits. The large pink mass in the lower left corner is a parenchyma cell, the other pieces are just fragments of cells that were broken during treatment.