Trustees of the University of the District of Columbia unanimously elected N. Joyce Payne last night as new chairman of the board at the troubled public university after Herbert O. Reid Sr. withdrew from the race.

Reid's surprise withdrawal came after several days of lobbying by both sides that apparently left the board divided on a replacement for outgoing Chairman Ronald H. Brown.

Payne, 44, executive director of a higher education organization, is a native Washingtonian who was appointed to the board in 1979. She is a graduate of D.C. Teachers' College, one of three institutions that were merged to form UDC in 1977.

The new chairman, who took the gavel from Brown in a packed meeting room on the UDC campus, becomes the board's chief steward at a critical point in UDC's history and at a time when the trustees and the university face a host of complex problems, some of which stem from the resignation last month of former president Robert L. Green.

Payne said she was aware of UDC's troubles but that she was optimistic about its future.

"For me, the public perception has been the most critical concern in the aftermath of the controversy surrounding Green's administration ," she said. "I would be remiss if I did not recognize that we have a perception problem with the public, but it is not irreversible."

"It is time to get back to our primary mission, the academic mission of UDC," she said.

The withdrawal of Reid's nomination and the election of Payne enabled the transfer of power on the board to occur with little public fanfare and with a show of unanimity that many trustees had hoped would be possible in the aftermath of the controversy over Green.

The nomination last month of Reid, who is legal counsel to Barry, had caused concern among some trustees who felt that under his chairmanship the mayor would be able to influence affairs of the university.

In a statement delivered to his colleagues at last night's board meeting, Reid said he was grateful for the nomination and that he felt that all of the trustees were qualifed to serve "beyond any personal acquaintance with individual council members or the mayor."

But he added that he had not sought the chairmanship and had only considered running for it at the suggestion of other trustees.

"I am indeed grateful for the nomination," Reid said. "Frankly, during the past month or so, I have vacillated because of my sense of public duty and public service on the one hand and demands upon my time on the other. I have reluctantly come to the conclusion not to accept the nomination."

He also said he sees a need for stability for the UDC Board, which he said lacks cohesiveness.

Reid, who holds an endowed chair at the Howard University Law School and is also active in a number of legal and civil rights organizations in addition to serving as Barry's legal counsel, said he did not feel that being UDC board chairman "would be a prudent employment of my energies."

Finally, Reid criticized the D.C. City Council's education committee, which began hearings on Monday on UDC's financial management and on the role of the trustees during the controversy over Green's use of UDC funds for travel, consulting and personal items.

"I do not see how I could function effectively as chair of this board in the present climate . . . . " Reid said. "The spectacle of the committee's last hearing is not something to which I would submit myself, nor do I understand how anyone of you can function effectively in this atmosphere."

Trustee Thomas A. Hart was elected board vice chairman, trustee Lucy Cohen was elected secretary and trustee Daniel I. Fivel was elected treasurer.

Brown left the board chairmanship after almost nine years as a trustee. His term as chairman expired last year but he remained at the helm at Barry's request and took the lead role in negotiating the terms of Green's resignation on Aug. 23. Trustee Lorraine Whitlock, who was appointed with Brown when the university first opened, left the board last night after receiving salutations from her colleagues.

Before the meeting adjourned, a number of trustees praised Brown for his leadership of the board during times of crisis. "He has performed an extraordinary public service in this city," said trustee Peter B. Edelman. "He has unimpeachable integrity and great talent."

The role of a new chairman has taken on particular significance because of an array of problems, including the search for a permanent replacement for Green, whose expenditures of thousands of dollars of university funds for travel, consulting, and personal items are under investigation by the FBI, the U.S. attorney's office, D.C. Auditor Otis H. Troupe and the D.C. council.

The Green controversy focused unprecedented attention on the board and its role in monitoring university finances.

Earlier this week, during the council education committee's first hearing on financial management at UDC, Fivel, chairman of the board's finance and audit committee, said trustees were unaware of financial abuses because a "breakdown" occurred at the university after Green instructed the internal auditor to report directly to the president's office instead of to the trustees.

Green, in his first public comment since his resignation, said in a telephone interview yesterday that Fivel was "buck-passing" and unfairly laying blame on UDC Auditor Samuel H. Halsey. He said he had told Halsey to report to him first only on requests for staff increases.

"I never said to Halsey, 'Don't report to the board on matters related to finance,' " Green said.

Green's departure already has triggered a scramble for power within the university and among different camps competing for senior positions.

When Reid surfaced as a candidate to replace Brown last month, several trustees questioned whether the independent university ought to have a close political adviser of Barry as board chairman.

Reid, 68, has been one of Barry's closest confidants and advisers since the 1960s, when both were heavily involved in the civil rights movement. In recent years, he has served as the mayor's point man on some of the most sensitive issues to confront the Barry administration.

At UDC, Reid played a key role with Brown in helping Green produce a 45-page report for the trustees in late July that defended his expenditures as president, and also reviewed all university documents before they were released to the news media