In wood anatomy, hardwoods are classified based on the distribution of vessel elements across an annual growth ring:
Ring-porous wood: Woods where earlywood vessels are distinctly larger in diameter and form a well-defined concentric ring, transitioning abruptly or semi-abruptly to much smaller latewood vessels. Classic Indian examples include Toona ciliata (Toon), Tectona grandis (Teak), Morus alba (Mulberry), and Melia azedarach.
In contrast, Diospyros melanoxylon, Acacia catechu, and Mesua ferrea possess diffuse-porous wood, where vessels are distributed fairly uniformly in size throughout the growth ring.