The National Society Ladies of the Thistle was organized in 1988 with national headquarters located in San Antonio, Texas. The organizing governor general was Leta Proctor Baughn of San Antonio. The purpose of the organization is to commemorate the memory of the membership's Scottish ancestors who immigrated to Colonial America prior to July 4, 1776, and who withstood the hardships of early colonization to make a positive contribution to the founding of the United States of America. The object of the society is to increase the knowledge and stimulate the interest of its members in Scottish history and genealogy through research, reading, and lectures and to study the contributions made by Scottish ancestors to colonial progress. Women who are lineally descended from an acceptable Scottish ancestor are eligible for membership. An acceptable ancestor is a man or woman from Scotland who either immigrated to and settled in Colonial America prior to July 4, 1776, or those from other countries who are lineally descended from Scottish ancestors and later immigrated to and settled in Colonial America prior to July 4, 1776. Membership is by invitation and is classified as active, life, or honorary or emeritus. The board of directors is headed by the governor general and administers the affairs of the society between its semiannual meetings, which are held in the spring and fall in San Antonio. The National Wildflower Research Center in Austin has been designated as the recipient of annual contributions by members and the society.