Executive Order in 1961 for members of the U.S Army Special Forces to gain approval and authorization to wear the Green Beret. The Department of the Army made its second distinctive beret uniform concession in 1975 when the U.S Army Rangers were authorized wear of the black beret Tan effective 15 June 2001.
T he Special Forces distinctive shoulder sleeve insignia SSI is well known in U.S. military circles but its origin is not. From its inception in 1952 Special Forces SF sought a distinctive symbol to distinguish itself from other Army units. The most significant symbol is the Green Beret.
Today only Special Forcesqualified soldiers may wear the green beret making obsolete the unit striker bar under the flash. Each Special Forces Group has its own unique beret flash which is worn by all members assigned to the unit Special Forcesqualified soldiers wear it on the green beret while support personnel wear it on the maroon beret.
In the United States Army the green beret may be worn only by soldiers awarded the Special Forces Tab signifying they have qualified as Special Forces soldiers.. U.S. Army Special Forces wear the green beret because of their link to the British Commandos of World War II. The first Ranger unit commonly known as Darby39s Rangers was formed in Northern Ireland during the summer of 1942.
To answer another of your questions Special Forces Green Berets were the only outfit to wear an authorized beret untill Feb. 1974. At that time the 509th B.C.T. in Vicenza Italy was the first unit approved to wear the maroon beretat all times.
For the most part soldiers who are Special Forces qualified wear the green beret. Sometimes Special Forces soldiers are assigned to a nonSF unit where they might not be authorized to wear the green beret its up to the discretion of the commander.
Green Berets work in twelveman teams and they typically wear the same Army fatigues as regular soldiers. They are easily distinguished through their green berets which are only worn on installations in the U.S. their Special Forces patch and a patch of a dagger going through a lightning bolt.
Six Ranger battalions were formed for war service. Soldiers who completed the rigorous British training won the right to wear the British Commando green beret. wear was also discontinued until U.S. Army formed its first Special Forces organizations during 1952. It did not become the official headgear worn by Army Special Forces until 1961.