Abstract: The examination of leaf sheath with fibrovascular bundles in windmill palm showed that the leaf sheath was developed from a knot part, and changed its color from white to dark brown with parenchyma cells inactivating during maturation. In parallel with the color change of the leaf sheath, a qualitative change of its chemical components was detected by Fourier transform infrared spectroscopic analysis. It revealed that the lignin contents increases relatively with the decrease of cellulose and hemicellulose contents. According to light microscopic and scanning electron microscopic observation, a fibrovascular bundle was surrounded by a large number of silica bodies in a single layer of stegmata cells. The high durability of palm fibrovascular bundles could be related to the presence of silica bodies.