Vessels: Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Two distinct vessel diameter classes absent. Average tangential vessel diameter 115–230–295 µm. Average number of vessels/mm² 1–2. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) (8–)9–12(–13) µm, vestured. Vessel-ray pits with distinct borders or with reduced borders or apparently simple, similar to intervessel pits, rounded or angular. Other deposits in heartwood vessels present (orange brown).

Tracheids and fibres: Fibres of medium wall thickness. Average fibre length 1035–1380–1660 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered.

Axial parenchyma: Axial parenchyma banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates (short tangential lines without contact to vessels). Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma winged. Axial parenchyma fusiform and as strands. Average number of cells per axial parenchyma strand 2.

Rays: Rays 12–17 per tangential mm, exclusively uniseriate. Height of large rays up to 500 µm. Rays composed of a single cell type. Homocellular ray cells procumbent.

Storied structures: Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied.

Secretary structures: Intercellular canals absent.

Mineral inclusions: Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size, or enlarged (idioblasts). Silica not observed.

Pterocarpus santalinus. L  Cross Section

Pterocarpus santalinus. L Radial Section

Pterocarpus santalinus. L Tangential Section