In 1971, when a program to identify sites associated with important black contributions to American history was initiated, there were only four such places on the list of National Historic Landmarks.

Today there are 76 on the list, 22 of them noted in an exhibition, "Black American Landmarks," at the headquarters building of the American Institute of Architects. Though the events and lives recalled by these buildings were remarkable, many are not widely known. This in itself is evidence (as if it really were necessary) that the need to identify and commemorate the sites was long ignored.

"Our work was only a drop in the bucket when you consider that there are well over 2,000 National Historic Landmarks nationwide, but it was a logical first step and we're proud of it," says Robert de Forrest, who with his brother Vincent headed the Afro-American Bicentennial Corp., which undertook the initial study for the National Park Service.

Sixty sites achieved landmark status through 1977 as a result of the corporation's work. Twelve have been added since. Architecturally the buildings range from the ordinary to the grand.

A much-altered Philadelphia row house pictured in the show, for instance, is not terribly distinguished, but it tells of the apprentice years of Henry Ossawa Tanner, the great black painter who, as it turned out, was more honored in Europe than in his native land during his lifetime. By contrast, the Villa Lewaro in Irvington, N.Y., is an elegant Italianate mansion in excellent repair. It was designed by Vertner Tandy, a black architect, for Madame C.J. Walker, "the first black woman millionaire in the business world."

In general the buildings in the show reflect the regional architectural styles of the time they were built. Only four were designed or built by blacks. In addition to Villa Lewaro, these include the African Meeting House in Boston, built by black laborers and craftsmen in 1806; the Chapelle Administration Building in Columbia, S.C., designed by J.A. Lankford, the dean of black American architects, and the African House and the early plantation building at Yucca plantation in Melrose, La.

"We still suffer from a shortage of black architects," said David Olan Meeker Jr., executive vice president of the American Institute of Architects, in a speech at the AIA headquarters Tuesday. AIA figures bear him out. Of the 41,386 members and associate members of the national organization, only 243 identified themselves as black on the membership forms.

"This is not surprising," said Marshall Purnell, treasurer of the National Organization of Minority Architects, though it is misleading, he said. "I'd have to put the figure at about 2,500 licensed and practicing black architects nationally." The reason for the discrepancy, he said, is that "AIA is not perceived as being responsive to minority concerns."

The two structures at Yucca plantation, with their wide, overhanging roofs, are the only ones in the show that directly demonstrate African-inspired elements of design. They also tell of one of the more remarkable and lesser known episodes of black American history. The plantation (now known as Melrose Plantation) was established between 1775 and 1800 by Madame Marie Therese Coin-Coin Metoyer, a former slave who later became a slave owner herself. But the design of the early buildings "reflect Madame Metoyer's refusal to adopt European models of architecture around her," according to the original announcement of their elevation to national landmark status.

Each of the 76 black landmarks has been faithfully documented by architectural draftsmen working for the Historic American Buildings Survey (HABS), a National Park Service program established 50 years ago and operated in collaboration with the AIA and the Library of Congress. In addition to photographs and terse captions, the exhibition contains reproductions of a few of the excellent HABS drawings. The show was organized by the Smithsonian Institution Traveling Exhibition Service. It will be on view at the AIA headquarters, 1735 New York Ave. NW, through Sept. 11.