The Maryland Senate tacked on a potential "killer" amendment today before approving legislation that would strip the expensive Burning Tree Club of Bethesda of a tax exemption because it discriminates against women.

The amendment, passed 24 to 14, exempts groups such as the Elks, Moose and Masons because they are charitable organizations. Sen. Stewart Bainum Jr. (D-Montgomery), the bill's chief sponsor, unsuccessfully fought the amendment because the action means the bill must go back to the House, where it was barely approved 10 days ago. Bainum said he fears opponents in the House will stall consideration and attempt to prevent a vote before the legislature ends at midnight Monday.

The bill would take away a $152,000 annual property tax exemption that the 600-member, all-male club gets for providing green space in the urbanized county. A club officer, testifying against the measure, warned that passage might make Burning Tree, which charges a $12,000 initiation fee and $1,700 annual dues, a rich man's club, because rather than admit women, it would increase dues to offset the tax deduction.

Even though it would apply only in Montgomery County--and as a result of today's amendment, apparently only to the one club--the amendment has become controversial.

The amended bill was approved by the full Senate, 38 to 6, after more than an hour of often loud arguments and angry accusations.

"My good friend Del. Paul Weisengoff has assured me that if the bill comes back to the House he'll do everything he can to kill it," Bainum said. "An amendment to the bill could mean death for it."

It must now be approved by the House Ways and Means Committee and then the full House. And this afternoon, opponents began delaying tactics.

Weisengoff was true to his word, fighting the legislation as soon as it was back in the House. When the measure passed the House 10 days ago, Weisengoff walked up to Del. Mary Boergers (D-Montgomery) and said, "You broads ain't in the pool yet." Knowing that Weisengoff is the legislature's master of parliamentary maneuvering, Bainum had worked to keep amendments off the measure.

"Several guys who promised not to vote for an amendment did," a disappointed Bainum said as he went to the House to try to round up the votes he will need to get the bill out of the Ways and Means Committee.

Bainum and other supporters fended off a motion to "special order," which is the official term for delaying consideration of a bill. That tactic, tried by Sen. Raymond E. Beck (R-Carroll), would have delayed a vote until Monday, effectively killing the bill, as there would have not been enough time to get it through both houses on the last day of the session.

Sen. Margaret C. Schweinhaut, the only woman senator from Montgomery, voted for the bill when it was before the delegation, but today she voted for the motion to special order, even after proponents pointed out the move would kill the bill.

The motion to special order was defeated 25 to 18, largely because of Sen. James Clark Jr. (D-Howard) and Sen. Julian L. Lapides (D-Baltimore).

"To vote for special order is the easy way out," Clark said, "and we are sent down here to make tough decisions. I know this is one of them. But the question is, what is right and what is wrong? This bill is right. The Constitution says so and I think most of us believe it. Let's vote on this thing one way or the other."

Lapides, long the Senate's liberal conscience, said, "I often think that it would be easier to pass a discrimination bill in this state than an anti-discrimination bill. And, unfortunately, we'd do it with a lot less controversy and talk."