They called a caucus of black convention delegates here this morning, and nobody came.

"It was embarrassing," said Democratic National Committee member Jessie Rattley of Newport News, Va., one of the organizers.

Poor communications probably had something to do with it, but it was just as likely that most black delegates had more important things to do. They were off working somewhere else, at state caucuses, at union meetings, with feminists or gay rights delegates. Some blacks were at work in the rarefied top-floor suites of the Sheraton Centre Hotel among President Carter's top lieutenants, deciding presidential tactics for the convention floor.

The empty caucus room is an apt expression of how much has changed about black politics and black participation in the Democratic Party. A decade ago at convention time, the black caucus was the place where every black delegate and leader convened to argue about strategy and express his or her solidarity. Today, there are many more blacks on the convention floor -- and they are all over the place, no longer unified, no longer isolated.

This convention has 481 black delegates -- more than 10 times the number at the convention that nominated John F. Kennedy for president in 1960 and about 150 more than in 1976. The historic growth stemmed from the party's affirmative action rules and the Democrats' increasing reliance on the black vote.

In this swelling rank, there are common concerns on the key economic issues of jobs and housing, but black delegates are spread out over a variety of special interest groups and conflicting political positions. About two-thirds of blacks are pledged to Carter, the rest to Sen. Edward M. Kennedy.

After Kennedy's defeat Monday night, Denise Bacote, a lawyer from Manhattan, sat in the New York delegation, her chin on her palm, looking glum.

"I'm sad," she said. "I don't know where we're going from here."

On the other side of Madison Square Garden, Ollie H. Burns, a retired librarian and Louisiana delegate, was applauding, her big straw hat with the American flag and the Jimmy Carter letters bobbing up and down. Everything, she said, had turned out as she hoped it would.

"I don't feel that Carter has done everything he promised, but one person can't do everything himself," she said.

Just as in the past, some black leaders invoked black unity to try to bring everyone together behind a single black position, but that appeal becomes less and less effective as blacks spread themselves across the spectrum of issues and candidates.

The maverick California congressman, Ronald V. Dellums, has announced a symbolic candidacy for the said, debate and discussion of issues affecting the poor. Dellums views with alarm the breakup of the tight black bloc.

"What has happened to us that we are no longer able to struggle for the poor, the destitute?" he asked some black delegates at an earlier caucus. "We have allowed ourselves to get too caught up in personalities and patronage."

That is the negative view. But White House aide Louis Martin -- whose involvement in Democratic politics stretches, back to 1932 when Franklin Roosevelt was nominated by a convention that had no black delegates -- believes the evolution of black participation is a trumph of change.

"Like it or not, we're mainstreaming," Martin said, beaming. "We can't complain that blacks are over in the corner being ignored."

There are flashy contrasts with the past. Sixteen years ago at the convention in Atlantic City, when blacks stood outside attempting to get in, they brought mule teams to symbolize their downtrodden status. After the opening of this convention last night, the black delegates went off to a disco party at Regine's the jet-set club on Park Avenue.

Given the heady influence of television coverage, some black leaders manage to create a public presence that doesn't quite match the reality of hard politics on the convention floor.

Millions of TV viewers have seen frequent glimpses in the past few days of the Rev. Jesse Jackson, head of Operation Push. Last night for instance, he was on the screen, interwalkout by black delegates.At the Sheraton Center where some black operatives of the Democratic National Committee watched Jackson on TV, there were irritated frowns. Jesse Jackson is not a delegate.

On the NBC "Today" show, where Jackson appeared this morning, correspondent Tom Brokaw wisecracked that Jackson appears on TV almost as much as Brokaw.

"There's a big difference," Jackson said," I don't get paid for it."

"You're right," Brokaw said. "That's a big difference."

What Jesse Jackson gets from television, of course, is political influence -- a way to raise issues and change minds, even though he lacks the concrete powers of elected delegate or public official. That's a traditional role in black politics -- the persuasive preacher -- and it's still very much alive.

But Jesse Jackson is not a wheel-horse among the blacks attending the convention. The black powers here are the big city mayors: Coleman Young of Detroit, Maynard Jackson of viewed as a leader of a threatened Atlanta and Richard Hatcher of Gary, Ind.

Young, chairman of the powerful Platform Committee, usually operates from the seclusion of his suite at the Sheraton Centre command post. Some white mayors often rely on reports from Jackson and Hatcher on President Carter's positions on the economic platform issues because the two have better access to top Carter strategists.

Monday night while Jesse Jackson was involved in the threatened walkout, Maynard Jackson was backstage at the Garden, unaware of the commotion. When asked about it, Mayor Jackson didn't bother to join the fray but went ahead with what he was scheduled to do -- take the convention podium to defend the Carter camp's oposition to the "open" convention rule.

Jesse Jackson explained to a meeting Monday that the black movement has evolved to the point where there are two complementary groups -- "tree shakers and jelly makers." The "tree shakers" like himself shake the apples down from the tree, and the 'jelly makers" like regular politicians make jelly and take it to market.

'Don't be fool enough to think you got that job on the basis of merit, you got it on the basis of power," Jackson told the black delegates.

The new reality of black politics is that there seem to be a lot more jelly makers nowadays than the tree shakers.

Among black delegates are state legislative representatives , school board and city council members, long time workers in Democratic community clubs, union operatives, and partisans for the Equal Rights Amendment and gay rights.

What is most striking about black delegates is how closely they resemble their white counterparts. According to a Washington Post survey of Democratic delegates, black delegates tend to be well-educated and well-off. About 70 per cent of them have been graduated from college and there are fewer black high school dropouts (about 4 per cent) than whites without a diploma (about 12 per cent). About 46 per cent of black delegates are in their 30s and 40s.

Though Jesse Jackson and other civil rights leaders emphasize deep disappointment with Carter in their speeches, black delegates tend to be more fervent supporters of the president than are the white delegates.

Like whites here, the black delegates overwhelmingly tend to support the ERA and to disagree just as vigorously with the idea of cutting federal taxes if it means cuts in social programs.

Black delegates are far more likely than whites to describe themselves as liberals. They tend to be slightly more enthusiastic about wage and price controls, national health insurance and a government guarantee of jobs for all who want to work. They tend to be less vigorous in their opposition to reinstitution of the draft and construction of nuclear power plants than are white delegates.

Nationally, the black voting age population still is concentrated in the South, but its growth in recent years has been in the Northeast and the northern states of the Midwest, according to the Joint Center for Political Studies, a respected black think tank based in Washington. There now are about 17 million blacks of voting age, according to U.S. Census estimates, or roughly 10.6 per cent of the electorate.

But the Joint Center also notes the steady decline of black voting. About 58 per cent of blacks eligible to vote reported that they had done so in the 1968 election. That proportion declined to 52 per cent in 1972 and 49 per cent in 1976.

New York convention delegate Denise Bacote said she knows why, Bacote works at registering voters in Manhattan's Upper West Side, where the middle class in coopertive apartments are next to low-rise public housing projects. Some residents of the projects would listen to her she said. Other would not.

"Older people," she said, "would tell you they had voted in earlier elections and they had seen no appreciable difference in the quality of their lives. Other people would tell you that they simply weren't interested."

"I don't think the political process is ever going to get you to straighten out this process of last hired, first fired," Martin said. "I just don't understand why we bypass the private sector. I don't understand why the civil rights leadership doesn't put heat on the private sector."

Nevertheless, the political leverage of blacks -- both tree shakers and jelly makers -- has won the admiration and envy of another minority group: the Hispanics.

Miami Mayor Maurice Ferre was talking about deep divisions among the 204 Hispanic delegates here -- Cubans divided against Mexicans, and even rifts between Puerto Ricans from New York and those who still live on their home island.

"The black community in America is a united community whose differences may be social class, but black Americans do not separate themselves into sub-ethnic classes," Ferre said "We have the very same [social and economic] problems as blacks and we have to have the same solutions that the black community does have.