Possible Clues:

• Tony winner 'August: ___ County'
• Amerindian not starting a quantity of medicine
• Native American tribe with a reservation in Oklahoma
• An inedible orange
• ___ orange (inedible fruit)
• Missouri river or Indian
• People of America having very big part in history
• Age so (anag) — member of a Native American people
• Truman Dam river
• With 21-Across, native Oklahoma group