Abstract: The purple variety and the white variety of cat`s whiskers (Orthosiphon stamineus Benth), a medicinal plant with diuretic and anti-diabetic properties, could be mistakenly considered as the same type if not carefully observed because most of their external morphological characters were similar. Present morphological studies showed that these two varieties could be identified by their floral and leaf morphology. The purple variety produced ovate shape leaves with acute apex, truncate base and purple venation. Light yellowish spots were scattered unevenly on both the adaxial and abaxial surfaces of the leaves. The white variety produced rhomboid shaped leaves without any colored spots with acuminate apex, obtuse base and light green venation. The two most distinct floral characters were the colors of corolla and calyx. The purple variety produced light purple tint at the lobes of the two-lipped corolla with maroon calyx while the petals of the white variety was totally white without purple tint at the edge of the petal lobes and green calyx. The micro-structures of leaves, anthers, stigma and pollen grains were similar for both varieties.