The logo made by the Soroptimist International Single Club in the 1920s depicted a young woman and the leaves of an oak. The new stamp issued by San Marino Post shows this lady sowing seeds of oak and she sees the plant growing. The oak is a strong and long-lived tree, widespread in the territory of San Marino and its branches are a constituent element of the Coat of arms of the Republic of San Marino. Sowing seeds is a symbol of making plans with perseverance and fulfilling them with passion and commitment. The rays of light spreading from the woman mean that the women of the Soroptimist International Single Club pursue their humanitarian purposes with willpower and tenacity. Yellow and blue are the colors of the Club and their union forms green.