Ann Richards was the head of the executive branch of a state government.
Dorothy Ann Willis Richards ( September 1 , 1933 -- September 13 , 2006 ) was an American politician and the 45th Governor of Texas from 1991 to 1995 . The governor of the State of Oklahoma is the head of state for the U.S. state of Oklahoma . Under the Oklahoma Constitution , the governor is also the head of government , serving as the chief executive of the Oklahoma executive branch , of the government of Oklahoma . A parliamentary system is a system of democratic governance of a state where the executive branch derives its democratic legitimacy from its ability to command the confidence of the legislative branch , typically a parliament , and is also held accountable to that parliament .