The long presidential primary season ends today with contests stretching from coast to coast.

California, New Jersey and Ohio hold the three most glamorous primaries of the day. Rhode Island, West Virginia, South Dakota, Montana and New Mexico also have contests in both parties. Mississippi has a Republican primary only.

On the Democratic side, President Carter is expected to win enough of the 696 delegates at stake to put him over the 1,666 needed for nomination.Nonetheless, Sen. Edward M. Kennedy (D-Mass.) still clings to the hope that a strong showing today will allow him to shake enough delegates away from Carter to win the nomination at the convention in New York next August.

Carter had invested more time and money in Ohio, a state he won in 1976, and is the favorite there. The races in New Jersey and California are tighter.

On the Republican side, Ronald Reagan will use his unopposed victories to launch his fall campaign.

Californians also will vote on several ballot initiatives, including Proposition 9, which would cut state income taxes in half. Public opinion polls show it running behind, a sign that the tax revolt that began two years ago in California with Proposition 13 may be cooling.