tangential section: Pinus stem magnification: 400x iron-alum hematoxylin and safranin stain

Gymnosperms like Pinus rely entirely on tracheids for water flow and mechanical support. True xylem vessels and wood parenchyma are lacking. While fibers are generally absent older stems may contain some fiber tracheids.

The uniform wood of Pinus consists almost entirely of longitudinally oriented bands of narrow, pale staining tracheids interrupted by short bands of horizontally oriented xylem rays. Xylem rays, usually one cell thick and a few cells high, are composed of clear, thin walled parenchyma cells.